nostrdb

nostrdb.c (192618B)

---

 
 #include "nostrdb.h"
 #include "jsmn.h"
 #include "hex.h"
 #include "cursor.h"
 #include "random.h"
 #include "ccan/crypto/sha256/sha256.h"
 #include "bolt11/bolt11.h"
 #include "bolt11/amount.h"
 #include "lmdb.h"
 #include "util.h"
 #include "cpu.h"
 #include "block.h"
 #include "threadpool.h"
 #include "thread.h"
 #include "protected_queue.h"
 #include "memchr.h"
 #include "print_util.h"
 #include <stdlib.h>
 #include <limits.h>
 #include <assert.h>
 
 #include "bindings/c/profile_json_parser.h"
 #include "bindings/c/profile_builder.h"
 #include "bindings/c/meta_builder.h"
 #include "bindings/c/meta_reader.h"
 #include "bindings/c/profile_verifier.h"
 #include "secp256k1.h"
 #include "secp256k1_ecdh.h"
 #include "secp256k1_schnorrsig.h"
 
 #define max(a,b) ((a) > (b) ? (a) : (b))
 #define min(a,b) ((a) < (b) ? (a) : (b))
 
 // the maximum number of things threads pop and push in bulk
 #define THREAD_QUEUE_BATCH 4096
 
 // maximum number of active subscriptions
 #define MAX_SUBSCRIPTIONS 256
 #define MAX_SCAN_CURSORS 12
 #define MAX_FILTERS    16
 
 // the maximum size of inbox queues
 static const int DEFAULT_QUEUE_SIZE = 32768;
 
 // 2mb scratch size for the writer thread
 static const int DEFAULT_WRITER_SCRATCH_SIZE = 2097152;
 
 // increase if we need bigger filters
 #define NDB_FILTER_PAGES 64
 
 #define ndb_flag_set(flags, f) ((flags & f) == f)
 
 #define NDB_PARSED_ID           (1 << 0)
 #define NDB_PARSED_PUBKEY       (1 << 1)
 #define NDB_PARSED_SIG          (1 << 2)
 #define NDB_PARSED_CREATED_AT   (1 << 3)
 #define NDB_PARSED_KIND         (1 << 4)
 #define NDB_PARSED_CONTENT      (1 << 5)
 #define NDB_PARSED_TAGS         (1 << 6)
 #define NDB_PARSED_ALL          (NDB_PARSED_ID|NDB_PARSED_PUBKEY|NDB_PARSED_SIG|NDB_PARSED_CREATED_AT|NDB_PARSED_KIND|NDB_PARSED_CONTENT|NDB_PARSED_TAGS)
 
 typedef int (*ndb_migrate_fn)(struct ndb_txn *);
 typedef int (*ndb_word_parser_fn)(void *, const char *word, int word_len,
 				  int word_index);
 
 // these must be byte-aligned, they are directly accessing the serialized data
 // representation
 #pragma pack(push, 1)
 
 union ndb_packed_str {
 	struct {
 		char str[3];
 		// we assume little endian everywhere. sorry not sorry.
 		unsigned char flag; // NDB_PACKED_STR, etc
 	} packed;
 
 	uint32_t offset;
 	unsigned char bytes[4];
 };
 
 struct ndb_tag {
 	uint16_t count;
 	union ndb_packed_str strs[0];
 };
 
 struct ndb_tags {
 	uint16_t padding;
 	uint16_t count;
 };
 
 // v1
 struct ndb_note {
 	unsigned char version;    // v=1
 	unsigned char padding[3]; // keep things aligned
 	unsigned char id[32];
 	unsigned char pubkey[32];
 	unsigned char sig[64];
 
 	uint64_t created_at;
 	uint32_t kind;
 	uint32_t content_length;
 	union ndb_packed_str content;
 	uint32_t strings;
 	// nothing can come after tags since it contains variadic data
 	struct ndb_tags tags;
 };
 
 #pragma pack(pop)
 
 
 struct ndb_migration {
 	ndb_migrate_fn fn;
 };
 
 struct ndb_profile_record_builder {
 	flatcc_builder_t *builder;
 	void *flatbuf;
 };
 
 // controls whether to continue or stop the json parser
 enum ndb_idres {
 	NDB_IDRES_CONT,
 	NDB_IDRES_STOP,
 };
 
 // closure data for the id-detecting ingest controller
 struct ndb_ingest_controller
 {
 	MDB_txn *read_txn;
 	struct ndb_lmdb *lmdb;
 	struct ndb_note *note;
 	uint64_t note_key;
 };
 
 enum ndb_writer_msgtype {
 	NDB_WRITER_QUIT, // kill thread immediately
 	NDB_WRITER_NOTE, // write a note to the db
 	NDB_WRITER_PROFILE, // write a profile to the db
 	NDB_WRITER_DBMETA, // write ndb metadata
 	NDB_WRITER_PROFILE_LAST_FETCH, // when profiles were last fetched
 	NDB_WRITER_BLOCKS, // write parsed note blocks
 	NDB_WRITER_MIGRATE, // migrate the database
 	NDB_WRITER_NOTE_RELAY, // we already have the note, but we have more relays to write
 };
 
 // keys used for storing data in the NDB metadata database (NDB_DB_NDB_META)
 enum ndb_meta_key {
 	NDB_META_KEY_VERSION = 1
 };
 
 struct ndb_json_parser {
 	const char *json;
 	int json_len;
 	struct ndb_builder builder;
 	jsmn_parser json_parser;
 	jsmntok_t *toks, *toks_end;
 	int i;
 	int num_tokens;
 };
 
 // useful to pass to threads on its own
 struct ndb_lmdb {
 	MDB_env *env;
 	MDB_dbi dbs[NDB_DBS];
 };
 
 struct ndb_writer {
 	struct ndb_lmdb *lmdb;
 	struct ndb_monitor *monitor;
 
 	int scratch_size;
 	uint32_t ndb_flags;
 	void *queue_buf;
 	int queue_buflen;
 	pthread_t thread_id;
 
 	struct prot_queue inbox;
 };
 
 struct ndb_ingester {
 	struct ndb_lmdb *lmdb;
 	uint32_t flags;
 	struct threadpool tp;
 	struct prot_queue *writer_inbox;
 	void *filter_context;
 	ndb_ingest_filter_fn filter;
 };
 
 struct ndb_filter_group {
 	struct ndb_filter filters[MAX_FILTERS];
 	int num_filters;
 };
 
 struct ndb_subscription {
 	uint64_t subid;
 	struct ndb_filter_group group;
 	struct prot_queue inbox;
 };
 
 struct ndb_monitor {
 	struct ndb_subscription subscriptions[MAX_SUBSCRIPTIONS];
 	ndb_sub_fn sub_cb;
 	void *sub_cb_ctx;
 	int num_subscriptions;
 
 	// monitor isn't a full inbox. We want pollers to be able to poll
 	// subscriptions efficiently without going through a message queue, so
 	// we use a simple mutex here.
 	pthread_mutex_t mutex;
 };
 
 struct ndb {
 	struct ndb_lmdb lmdb;
 	struct ndb_ingester ingester;
 	struct ndb_monitor monitor;
 	struct ndb_writer writer;
 	int version;
 	uint32_t flags; // setting flags
 	// lmdb environ handles, etc
 };
 
 ///
 /// Query Plans
 ///
 /// There are general strategies for performing certain types of query
 /// depending on the filter. For example, for large contact list queries
 /// with many authors, we simply do a descending scan on created_at
 /// instead of doing 1000s of pubkey scans.
 ///
 /// Query plans are calculated from filters via `ndb_filter_plan`
 ///
 enum ndb_query_plan {
 	NDB_PLAN_KINDS,
 	NDB_PLAN_IDS,
 	NDB_PLAN_AUTHORS,
 	NDB_PLAN_AUTHOR_KINDS,
 	NDB_PLAN_CREATED,
 	NDB_PLAN_TAGS,
 	NDB_PLAN_SEARCH,
 };
 
 // A id + u64 + timestamp
 struct ndb_id_u64_ts {
 	unsigned char id[32]; // pubkey, id, etc
 	uint64_t u64; // kind, etc
 	uint64_t timestamp;
 };
 
 // A clustered key with an id and a timestamp
 struct ndb_tsid {
 	unsigned char id[32];
 	uint64_t timestamp;
 };
 
 // A u64 + timestamp id. Just using this for kinds at the moment.
 struct ndb_u64_ts {
 	uint64_t u64; // kind, etc
 	uint64_t timestamp;
 };
 
 struct ndb_word
 {
 	const char *word;
 	int word_len;
 };
 
 struct ndb_search_words
 {
 	struct ndb_word words[MAX_TEXT_SEARCH_WORDS];
 	int num_words;
 };
 
 
 static inline int is_replaceable_kind(uint64_t kind)
 {
 	return kind == 0 || kind == 3
 		|| (10000 <= kind && kind < 20000)
 		|| (30000 <= kind && kind < 40000);
 }
 
 
 // ndb_text_search_key
 //
 // This is compressed when in lmdb:
 //
 //   note_id:    varint
 //   strlen:     varint
 //   str:        cstr
 //   timestamp:  varint
 //   word_index: varint
 //
 static int ndb_make_text_search_key(unsigned char *buf, int bufsize,
 				    int word_index, int word_len, const char *str,
 				    uint64_t timestamp, uint64_t note_id,
 				    int *keysize)
 {
 	struct cursor cur;
 	make_cursor(buf, buf + bufsize, &cur);
 
 	// TODO: need update this to uint64_t
 	// we push this first because our query function can pull this off
 	// quickly to check matches
 	if (!cursor_push_varint(&cur, (int32_t)note_id))
 		return 0;
 
 	// string length
 	if (!cursor_push_varint(&cur, word_len))
 		return 0;
 
 	// non-null terminated, lowercase string
 	if (!cursor_push_lowercase(&cur, str, word_len))
 		return 0;
 
 	// TODO: need update this to uint64_t
 	if (!cursor_push_varint(&cur, (int)timestamp))
 		return 0;
 
 	// the index of the word in the content so that we can do more accurate
 	// phrase searches
 	if (!cursor_push_varint(&cur, word_index))
 		return 0;
 
 	// pad to 8-byte alignment
 	if (!cursor_align(&cur, 8))
 		return 0;
 
 	*keysize = cur.p - cur.start;
 	assert((*keysize % 8) == 0);
 
 	return 1;
 }
 
 static int ndb_make_noted_text_search_key(unsigned char *buf, int bufsize,
 					  int wordlen, const char *word,
 					  uint64_t timestamp, uint64_t note_id,
 					  int *keysize)
 {
 	return ndb_make_text_search_key(buf, bufsize, 0, wordlen, word,
 					timestamp, note_id, keysize);
 }
 
 static int ndb_make_text_search_key_low(unsigned char *buf, int bufsize,
 					int wordlen, const char *word,
 					uint64_t since,
 					int *keysize)
 {
 	uint64_t note_id;
 	note_id = 0;
 	return ndb_make_text_search_key(buf, bufsize, 0, wordlen, word,
 					since, note_id, keysize);
 }
 
 static int ndb_make_text_search_key_high(unsigned char *buf, int bufsize,
 					 int wordlen, const char *word,
 					 uint64_t until,
 					 int *keysize)
 {
 	uint64_t note_id;
 	note_id = INT32_MAX;
 	return ndb_make_text_search_key(buf, bufsize, 0, wordlen, word,
 					until, note_id, keysize);
 }
 
 typedef int (*ndb_text_search_key_order_fn)(unsigned char *buf, int bufsize, int wordlen, const char *word, uint64_t timestamp, int *keysize);
 
 /** From LMDB: Compare two items lexically */
 static int mdb_cmp_memn(const MDB_val *a, const MDB_val *b) {
 	int diff;
 	ssize_t len_diff;
 	unsigned int len;
 
 	len = a->mv_size;
 	len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
 	if (len_diff > 0) {
 		len = b->mv_size;
 		len_diff = 1;
 	}
 
 	diff = memcmp(a->mv_data, b->mv_data, len);
 	return diff ? diff : len_diff<0 ? -1 : len_diff;
 }
 
 static int ndb_tag_key_compare(const MDB_val *a, const MDB_val *b)
 {
 	MDB_val va, vb;
 	uint64_t ts_a, ts_b;
 	int cmp;
 
 	va.mv_data = a->mv_data;
 	va.mv_size = a->mv_size - 8;
 
 	vb.mv_data = b->mv_data;
 	vb.mv_size = b->mv_size - 8;
 
 	if ((cmp = mdb_cmp_memn(&va, &vb)))
 		return cmp;
 
 	ts_a = *(uint64_t*)((unsigned char *)va.mv_data + va.mv_size);
 	ts_b = *(uint64_t*)((unsigned char *)vb.mv_data + vb.mv_size);
 
 	if (ts_a < ts_b)
 		return -1;
 	else if (ts_a > ts_b)
 		return 1;
 
 	return 0;
 }
 
 static int ndb_text_search_key_compare(const MDB_val *a, const MDB_val *b)
 {
 	struct cursor ca, cb;
 	uint64_t sa, sb, nid_a, nid_b;
 	MDB_val a2, b2;
 
 	make_cursor(a->mv_data, (unsigned char *)a->mv_data + a->mv_size, &ca);
 	make_cursor(b->mv_data, (unsigned char *)b->mv_data + b->mv_size, &cb);
 
 	// note_id
 	if (unlikely(!cursor_pull_varint(&ca, &nid_a) || !cursor_pull_varint(&cb, &nid_b)))
 		return 0;
 
 	// string size
 	if (unlikely(!cursor_pull_varint(&ca, &sa) || !cursor_pull_varint(&cb, &sb)))
 		return 0;
 
 	a2.mv_data = ca.p;
 	a2.mv_size = sa;
 
 	b2.mv_data = cb.p;
 	b2.mv_size = sb;
 
 	int cmp = mdb_cmp_memn(&a2, &b2);
 	if (cmp) return cmp;
 
 	// skip over string
 	ca.p += sa;
 	cb.p += sb;
 
 	// timestamp
 	if (unlikely(!cursor_pull_varint(&ca, &sa) || !cursor_pull_varint(&cb, &sb)))
 		return 0;
 
 	if      (sa < sb) return -1;
 	else if (sa > sb) return 1;
 
 	// note_id
 	if      (nid_a < nid_b) return -1;
 	else if (nid_a > nid_b) return 1;
 
 	// word index
 	if (unlikely(!cursor_pull_varint(&ca, &sa) || !cursor_pull_varint(&cb, &sb)))
 		return 0;
 
 	if      (sa < sb) return -1;
 	else if (sa > sb) return 1;
 
 	return 0;
 }
 
 static inline int ndb_unpack_text_search_key_noteid(
 		struct cursor *cur, uint64_t *note_id)
 {
 	if (!cursor_pull_varint(cur, note_id))
 		return 0;
 
 	return 1;
 }
 
 // faster peek of just the string instead of unpacking everything
 // this is used to quickly discard range query matches if there is no
 // common prefix
 static inline int ndb_unpack_text_search_key_string(struct cursor *cur,
 						    const char **str,
 						    int *str_len)
 {
 	uint64_t len;
 
 	if (!cursor_pull_varint(cur, &len))
 		return 0;
 
 	*str_len = len;
 
 	*str = (const char *)cur->p;
 
 	if (!cursor_skip(cur, *str_len))
 		return 0;
 
 	return 1;
 }
 
 // should be called after ndb_unpack_text_search_key_string. It continues
 // the unpacking of a text search key if we've already started it.
 static inline int
 ndb_unpack_remaining_text_search_key(struct cursor *cur,
 				     struct ndb_text_search_key *key)
 {
 	if (!cursor_pull_varint(cur, &key->timestamp))
 		return 0;
 
 	if (!cursor_pull_varint(cur, &key->word_index))
 		return 0;
 
 	return 1;
 }
 
 // unpack a fulltext search key
 //
 // full version of string + unpack remaining. This is split up because text
 // searching only requires to pull the string for prefix searching, and the
 // remaining is optional
 static inline int ndb_unpack_text_search_key(unsigned char *p, int len,
 				      struct ndb_text_search_key *key)
 {
 	struct cursor c;
 	make_cursor(p, p + len, &c);
 
 	if (!ndb_unpack_text_search_key_noteid(&c, &key->note_id))
 		return 0;
 
 	if (!ndb_unpack_text_search_key_string(&c, &key->str, &key->str_len))
 		return 0;
 
 	return ndb_unpack_remaining_text_search_key(&c, key);
 }
 
 // Copies only lowercase characters to the destination string and fills the rest with null bytes.
 // `dst` and `src` are pointers to the destination and source strings, respectively.
 // `n` is the maximum number of characters to copy.
 static void lowercase_strncpy(char *dst, const char *src, int n) {
 	int j = 0, i = 0;
 
 	if (!dst || !src || n == 0) {
 		return;
 	}
 
 	while (src[i] != '\0' && j < n) {
 		dst[j++] = tolower(src[i++]);
 	}
 
 	// Null-terminate and fill the destination string
 	while (j < n) {
 		dst[j++] = '\0';
 	}
 }
 
 static inline int ndb_filter_elem_is_ptr(struct ndb_filter_field *field) {
 	return field->elem_type == NDB_ELEMENT_STRING || field->elem_type == NDB_ELEMENT_ID;
 }
 
 // Copy the filter
 int ndb_filter_clone(struct ndb_filter *dst, struct ndb_filter *src)
 {
 	size_t src_size, elem_size, data_size;
 
 	memcpy(dst, src, sizeof(*src));
 
 	elem_size = src->elem_buf.end - src->elem_buf.start;
 	data_size = src->data_buf.end - src->data_buf.start;
 	src_size = data_size + elem_size;
 
 	// let's only allow finalized filters to be cloned
 	if (!src || !src->finalized)
 		return 0;
 
 	dst->elem_buf.start = malloc(src_size);
 	dst->elem_buf.end = dst->elem_buf.start + elem_size;
 	dst->elem_buf.p = dst->elem_buf.end;
 
 	dst->data_buf.start = dst->elem_buf.start + elem_size;
 	dst->data_buf.end = dst->data_buf.start + data_size;
 	dst->data_buf.p = dst->data_buf.end;
 
 	if (dst->elem_buf.start == NULL)
 		return 0;
 
 	memcpy(dst->elem_buf.start, src->elem_buf.start, src_size);
 
 	return 1;
 }
 
 // "Finalize" the filter. This resizes the allocated heap buffers so that they
 // are as small as possible. This also prevents new fields from being added
 int ndb_filter_end(struct ndb_filter *filter)
 {
 #ifdef NDB_LOG
 	size_t orig_size;
 #endif
 	size_t data_len, elem_len;
 	if (filter->finalized == 1)
 		return 0;
 
 	// move the data buffer to the end of the element buffer and update
 	// all of the element pointers accordingly
 	data_len = filter->data_buf.p - filter->data_buf.start;
 	elem_len = filter->elem_buf.p - filter->elem_buf.start;
 #ifdef NDB_LOG
 	orig_size = filter->data_buf.end - filter->elem_buf.start;
 #endif
 
 	// cap the elem buff
 	filter->elem_buf.end = filter->elem_buf.p;
 
 	// move the data buffer to the end of the element buffer
 	memmove(filter->elem_buf.p, filter->data_buf.start, data_len);
 
 	// realloc the whole thing
 	filter->elem_buf.start = realloc(filter->elem_buf.start, elem_len + data_len);
 	filter->elem_buf.end = filter->elem_buf.start + elem_len;
 	filter->elem_buf.p = filter->elem_buf.end;
 
 	filter->data_buf.start = filter->elem_buf.end;
 	filter->data_buf.end = filter->data_buf.start + data_len;
 	filter->data_buf.p = filter->data_buf.end;
 
 	filter->finalized = 1;
 
 	ndb_debug("ndb_filter_end: %ld -> %ld\n", orig_size, elem_len + data_len);
 
 	return 1;
 }
 
 static inline struct ndb_filter_elements *
 ndb_filter_get_elements_by_offset(const struct ndb_filter *filter, int offset)
 {
 	struct ndb_filter_elements *els;
 
 	if (offset < 0)
 		return NULL;
 
 	els = (struct ndb_filter_elements *)(filter->elem_buf.start + offset);
 
 	if ((unsigned char *)els > filter->elem_buf.p)
 		return NULL;
 
 	return els;
 }
 
 struct ndb_filter_elements *
 ndb_filter_current_element(const struct ndb_filter *filter)
 {
 	return ndb_filter_get_elements_by_offset(filter, filter->current);
 }
 
 struct ndb_filter_elements *
 ndb_filter_get_elements(const struct ndb_filter *filter, int index)
 {
 	if (filter->num_elements <= 0)
 		return NULL;
 
 	if (index > filter->num_elements-1)
 		return NULL;
 
 	return ndb_filter_get_elements_by_offset(filter, filter->elements[index]);
 }
 
 static inline unsigned char *
 ndb_filter_elements_data(const struct ndb_filter *filter, int offset)
 {
 	unsigned char *data;
 
 	if (offset < 0)
 		return NULL;
 
 	data = filter->data_buf.start + offset;
 	if (data > filter->data_buf.p)
 		return NULL;
 
 	return data;
 }
 
 unsigned char *
 ndb_filter_get_id_element(const struct ndb_filter *filter, const struct ndb_filter_elements *els, int index)
 {
 	return ndb_filter_elements_data(filter, els->elements[index]);
 }
 
 const char *
 ndb_filter_get_string_element(const struct ndb_filter *filter, const struct ndb_filter_elements *els, int index)
 {
 	return (const char *)ndb_filter_elements_data(filter, els->elements[index]);
 }
 
 uint64_t *
 ndb_filter_get_int_element_ptr(struct ndb_filter_elements *els, int index)
 {
 	return &els->elements[index];
 }
 
 uint64_t
 ndb_filter_get_int_element(const struct ndb_filter_elements *els, int index)
 {
 	return els->elements[index];
 }
 
 int ndb_filter_init_with(struct ndb_filter *filter, int pages)
 {
 	struct cursor cur;
 	int page_size, elem_size, data_size, buf_size;
 
 	page_size = 4096; // assuming this, not a big deal if we're wrong
 
 	buf_size = page_size * pages;
 	elem_size = buf_size / 4;
 	data_size = buf_size - elem_size;
 
 	unsigned char *buf = malloc(buf_size);
 	if (!buf)
 		return 0;
 
 	// init memory arena for the cursor
 	make_cursor(buf, buf + buf_size, &cur);
 
 	cursor_slice(&cur, &filter->elem_buf, elem_size);
 	cursor_slice(&cur, &filter->data_buf, data_size);
 
 	// make sure we are fully allocated
 	assert(cur.p == cur.end);
 
 	// make sure elem_buf is the start of the buffer
 	assert(filter->elem_buf.start == cur.start);
 
 	filter->num_elements = 0;
 	filter->elements[0] = 0;
 	filter->current = -1;
 	filter->finalized = 0;
 
 	return 1;
 }
 
 int ndb_filter_init(struct ndb_filter *filter) {
 	return ndb_filter_init_with(filter, NDB_FILTER_PAGES);
 }
 
 void ndb_filter_destroy(struct ndb_filter *filter)
 {
 	if (filter->elem_buf.start)
 		free(filter->elem_buf.start);
 
 	memset(filter, 0, sizeof(*filter));
 }
 
 static const char *ndb_filter_field_name(enum ndb_filter_fieldtype field)
 {
 	switch (field) {
 	case NDB_FILTER_IDS: return "ids";
 	case NDB_FILTER_AUTHORS: return "authors";
 	case NDB_FILTER_KINDS: return "kinds";
 	case NDB_FILTER_TAGS: return "tags";
 	case NDB_FILTER_SINCE: return "since";
 	case NDB_FILTER_UNTIL: return "until";
 	case NDB_FILTER_LIMIT: return "limit";
 	case NDB_FILTER_SEARCH: return "search";
 	}
 
 	return "unknown";
 }
 
 static int ndb_filter_start_field_impl(struct ndb_filter *filter, enum ndb_filter_fieldtype field, char tag)
 {
 	int i;
 	struct ndb_filter_elements *els, *el;
 
 	if (ndb_filter_current_element(filter)) {
 		fprintf(stderr, "ndb_filter_start_field: filter field already in progress, did you forget to call ndb_filter_end_field?\n");
 		return 0;
 	}
 
 	// you can only start and end fields once
 	for (i = 0; i < filter->num_elements; i++) {
 		el = ndb_filter_get_elements(filter, i);
 		assert(el);
 		// TODO: fix this tags check to try to find matching tags
 		if (el->field.type == field && field != NDB_FILTER_TAGS) {
 			fprintf(stderr, "ndb_filter_start_field: field '%s' already exists\n",
 					ndb_filter_field_name(field));
 			return 0;
 		}
 	}
 
 	filter->current = filter->elem_buf.p - filter->elem_buf.start;
 	els = ndb_filter_current_element(filter);
 	assert(els);
 
 	// advance elem buffer to the variable data section
 	if (!cursor_skip(&filter->elem_buf, sizeof(struct ndb_filter_elements))) {
 		fprintf(stderr, "ndb_filter_start_field: '%s' oom (todo: realloc?)\n",
 				ndb_filter_field_name(field));
 		return 0;
 	}
 
 	els->field.type = field;
 	els->field.tag = tag;
 	els->field.elem_type = 0;
 	els->count = 0;
 
 	return 1;
 }
 
 int ndb_filter_start_field(struct ndb_filter *filter, enum ndb_filter_fieldtype field)
 {
 	return ndb_filter_start_field_impl(filter, field, 0);
 }
 
 int ndb_filter_start_tag_field(struct ndb_filter *filter, char tag)
 {
 	return ndb_filter_start_field_impl(filter, NDB_FILTER_TAGS, tag);
 }
 
 static int ndb_filter_add_element(struct ndb_filter *filter, union ndb_filter_element el)
 {
 	struct ndb_filter_elements *current;
 	uint64_t offset;
 
 	if (!(current = ndb_filter_current_element(filter)))
 		return 0;
 
 	offset = filter->data_buf.p - filter->data_buf.start;
 
 	switch (current->field.type) {
 	case NDB_FILTER_IDS:
 	case NDB_FILTER_AUTHORS:
 		if (!cursor_push(&filter->data_buf, (unsigned char *)el.id, 32))
 			return 0;
 		break;
 	case NDB_FILTER_KINDS:
 		offset = el.integer;
 		break;
 	case NDB_FILTER_SINCE:
 	case NDB_FILTER_UNTIL:
 	case NDB_FILTER_LIMIT:
 		// only one allowed for since/until
 		if (current->count != 0)
 			return 0;
 		offset = el.integer;
 		break;
 	case NDB_FILTER_SEARCH:
 		if (current->field.elem_type != NDB_ELEMENT_STRING) {
 			return 0;
 		}
 		if (!cursor_push(&filter->data_buf, (unsigned char *)el.string.string, el.string.len))
 			return 0;
 		if (!cursor_push_byte(&filter->data_buf, 0))
 			return 0;
 		break;
 	case NDB_FILTER_TAGS:
 		switch (current->field.elem_type) {
 		case NDB_ELEMENT_ID:
 			if (!cursor_push(&filter->data_buf, (unsigned char *)el.id, 32))
 				return 0;
 			break;
 		case NDB_ELEMENT_STRING:
 			if (!cursor_push(&filter->data_buf, (unsigned char *)el.string.string, el.string.len))
 				return 0;
 			if (!cursor_push_byte(&filter->data_buf, 0))
 				return 0;
 			break;
 		case NDB_ELEMENT_INT:
 			// ints are not allowed in tag filters
 		case NDB_ELEMENT_UNKNOWN:
 			return 0;
 		}
 		// push a pointer of the string in the databuf as an element
 		break;
 	}
 
 	if (!cursor_push(&filter->elem_buf, (unsigned char *)&offset,
 			 sizeof(offset))) {
 		return 0;
 	}
 
 	current->count++;
 
 	return 1;
 }
 
 static int ndb_filter_set_elem_type(struct ndb_filter *filter,
 				    enum ndb_generic_element_type elem_type)
 {
 	enum ndb_generic_element_type current_elem_type;
 	struct ndb_filter_elements *current;
 
 	if (!(current = ndb_filter_current_element(filter)))
 		return 0;
 
 	current_elem_type = current->field.elem_type;
 
 	// element types must be uniform
 	if (current_elem_type != elem_type && current_elem_type != NDB_ELEMENT_UNKNOWN) {
 		fprintf(stderr, "ndb_filter_set_elem_type: element types must be uniform\n");
 		return 0;
 	}
 
 	current->field.elem_type = elem_type;
 
 	return 1;
 }
 
 
 int ndb_filter_add_str_element_len(struct ndb_filter *filter, const char *str, int len)
 {
 	union ndb_filter_element el;
 	struct ndb_filter_elements *current;
 
 	if (!(current = ndb_filter_current_element(filter)))
 		return 0;
 
 	// only generic tags and search queries are allowed to have strings
 	switch (current->field.type) {
 	case NDB_FILTER_SINCE:
 	case NDB_FILTER_UNTIL:
 	case NDB_FILTER_LIMIT:
 	case NDB_FILTER_IDS:
 	case NDB_FILTER_AUTHORS:
 	case NDB_FILTER_KINDS:
 		return 0;
 	case NDB_FILTER_SEARCH:
 		if (current->count == 1) {
 			// you can't add more than one string to a search
 			return 0;
 		}
 		break;
 	case NDB_FILTER_TAGS:
 		break;
 	}
 
 	if (!ndb_filter_set_elem_type(filter, NDB_ELEMENT_STRING))
 		return 0;
 
 	el.string.string = str;
 	el.string.len = len;
 
 	return ndb_filter_add_element(filter, el);
 }
 
 int ndb_filter_add_str_element(struct ndb_filter *filter, const char *str)
 {
 	return ndb_filter_add_str_element_len(filter, str, strlen(str));
 }
 
 int ndb_filter_add_int_element(struct ndb_filter *filter, uint64_t integer)
 {
 	union ndb_filter_element el;
 	struct ndb_filter_elements *current;
 	if (!(current = ndb_filter_current_element(filter)))
 		return 0;
 
 	switch (current->field.type) {
 	case NDB_FILTER_IDS:
 	case NDB_FILTER_AUTHORS:
 	case NDB_FILTER_TAGS:
 	case NDB_FILTER_SEARCH:
 		return 0;
 	case NDB_FILTER_KINDS:
 	case NDB_FILTER_SINCE:
 	case NDB_FILTER_UNTIL:
 	case NDB_FILTER_LIMIT:
 		break;
 	}
 
 	if (!ndb_filter_set_elem_type(filter, NDB_ELEMENT_INT))
 		return 0;
 
 	el.integer = integer;
 
 	return ndb_filter_add_element(filter, el);
 }
 
 int ndb_filter_add_id_element(struct ndb_filter *filter, const unsigned char *id)
 {
 	union ndb_filter_element el;
 	struct ndb_filter_elements *current;
 
 	if (!(current = ndb_filter_current_element(filter)))
 		return 0;
 
 	// only certain filter types allow pushing id elements
 	switch (current->field.type) {
 	case NDB_FILTER_SINCE:
 	case NDB_FILTER_UNTIL:
 	case NDB_FILTER_LIMIT:
 	case NDB_FILTER_KINDS:
 	case NDB_FILTER_SEARCH:
 		return 0;
 	case NDB_FILTER_IDS:
 	case NDB_FILTER_AUTHORS:
 	case NDB_FILTER_TAGS:
 		break;
 	}
 
 	if (!ndb_filter_set_elem_type(filter, NDB_ELEMENT_ID))
 		return 0;
 
 	// this is needed so that generic filters know its an id
 	el.id = id;
 
 	return ndb_filter_add_element(filter, el);
 }
 
 static int ndb_tag_filter_matches(struct ndb_filter *filter,
 				  struct ndb_filter_elements *els,
 				  struct ndb_note *note)
 {
 	int i;
 	const unsigned char *id;
 	const char *el_str;
 	struct ndb_iterator iter, *it = &iter;
 	struct ndb_str str;
 
 	ndb_tags_iterate_start(note, it);
 
 	while (ndb_tags_iterate_next(it)) {
 		// we're looking for tags with 2 or more entries: ["p", id], etc
 		if (it->tag->count < 2)
 			continue;
 
 		str = ndb_tag_str(note, it->tag, 0);
 
 		// we only care about packed strings (single char, etc)
 		if (str.flag != NDB_PACKED_STR)
 			continue;
 
 		// do we have #e matching e (or p, etc)
 		if (str.str[0] != els->field.tag || str.str[1] != 0)
 			continue;
 
 		str = ndb_tag_str(note, it->tag, 1);
 
 		switch (els->field.elem_type) {
 		case NDB_ELEMENT_ID:
 			// if our filter element type is an id, then we
 			// expect a packed id in the tag, otherwise skip
 			if (str.flag != NDB_PACKED_ID)
 				continue;
 			break;
 		case NDB_ELEMENT_STRING:
 			// if our filter element type is a string, then
 			// we should not expect an id
 			if (str.flag == NDB_PACKED_ID)
 				continue;
 
 			break;
 		case NDB_ELEMENT_UNKNOWN:
 		default:
 			// For some reason the element type is not set. It's
 			// possible nothing was added to the generic filter?
 			// Let's just fail here and log a note for debugging
 			fprintf(stderr, "UNUSUAL ndb_tag_filter_matches: have unknown element type %d\n", els->field.elem_type);
 			return 0;
 		}
 
 		for (i = 0; i < els->count; i++) {
 			switch (els->field.elem_type) {
 			case NDB_ELEMENT_ID:
 				id = ndb_filter_get_id_element(filter, els, i);
 				if (!memcmp(id, str.id, 32))
 					return 1;
 				break;
 			case NDB_ELEMENT_STRING:
 				el_str = ndb_filter_get_string_element(filter, els, i);
 				if (!strcmp(el_str, str.str))
 					return 1;
 				break;
 			case NDB_ELEMENT_INT:
 				// int elements int tag queries are not supported
 			case NDB_ELEMENT_UNKNOWN:
 				return 0;
 			}
 		}
 	}
 
 	return 0;
 }
 
 struct search_id_state {
 	struct ndb_filter *filter;
 	struct ndb_filter_elements *els;
 	unsigned char *key;
 };
 
 static int compare_ids(const void *pa, const void *pb)
 {
         unsigned char *a = *(unsigned char **)pa;
         unsigned char *b = *(unsigned char **)pb;
 
         return memcmp(a, b, 32);
 }
 
 static int search_ids(const void *ctx, const void *mid_ptr)
 {
 	struct search_id_state *state;
 	unsigned char *mid_id;
 	uint32_t mid;
 
 	state = (struct search_id_state *)ctx;
 	mid = *(uint32_t *)mid_ptr;
 
 	mid_id = ndb_filter_elements_data(state->filter, mid);
 	assert(mid_id);
 
 	return memcmp(state->key, mid_id, 32);
 }
 
 static int compare_kinds(const void *pa, const void *pb)
 {
 
 	// NOTE: this should match type in `union ndb_filter_element`
 	uint64_t a = *(uint64_t *)pa;
 	uint64_t b = *(uint64_t *)pb;
 
 	if (a < b) {
 		return -1;
 	} else if (a > b) {
 		return 1;
 	} else {
 		return 0;
 	}
 }
 
 //
 // returns 1 if a filter matches a note
 static int ndb_filter_matches_with(struct ndb_filter *filter,
 				   struct ndb_note *note, int already_matched)
 {
 	int i, j;
 	struct ndb_filter_elements *els;
 	struct search_id_state state;
 
 	state.filter = filter;
 
 	for (i = 0; i < filter->num_elements; i++) {
 		els = ndb_filter_get_elements(filter, i);
 		state.els = els;
 		assert(els);
 
 		// if we know we already match from a query scan result,
 		// we can skip this check
 		if ((1 << els->field.type) & already_matched)
 			continue;
 
 		switch (els->field.type) {
 		case NDB_FILTER_KINDS:
 			for (j = 0; j < els->count; j++) {
 				if ((unsigned int)els->elements[j] == note->kind)
 					goto cont;
 			}
 			break;
 		case NDB_FILTER_IDS:
 			state.key = ndb_note_id(note);
 			if (bsearch(&state, &els->elements[0], els->count,
 				    sizeof(els->elements[0]), search_ids)) {
 				continue;
 			}
 			break;
 		case NDB_FILTER_AUTHORS:
 			state.key = ndb_note_pubkey(note);
 			if (bsearch(&state, &els->elements[0], els->count,
 				    sizeof(els->elements[0]), search_ids)) {
 				continue;
 			}
 			break;
 		case NDB_FILTER_TAGS:
 			if (ndb_tag_filter_matches(filter, els, note))
 				continue;
 			break;
 		case NDB_FILTER_SINCE:
 			assert(els->count == 1);
 			if (note->created_at >= els->elements[0])
 				continue;
 			break;
 		case NDB_FILTER_UNTIL:
 			assert(els->count == 1);
 			if (note->created_at < els->elements[0])
 				continue;
 			break;
 		case NDB_FILTER_SEARCH:
 			// TODO: matching search filters will need an accelerated
 			// data structure, like our minimal perfect hashmap
 			// idea for mutewords.
 			//
 			// We'll also want to store tokenized words in the filter
 			// itself, so that we can walk over each word and check
 			// the hashmap to see if the note contains at least
 			// one word.
 			//
 			// For now we always return true, since we assume
 			// the search index will be walked for these kinds
 			// of queries.
 			continue;
 		case NDB_FILTER_LIMIT:
 cont:
 			continue;
 		}
 
 		// all need to match
 		return 0;
 	}
 
 	return 1;
 }
 
 int ndb_filter_matches(struct ndb_filter *filter, struct ndb_note *note)
 {
 	return ndb_filter_matches_with(filter, note, 0);
 }
 
 // because elements are stored as offsets and qsort doesn't support context,
 // we do a dumb thing where we convert elements to pointers and back if we
 // are doing an id or string sort
 static void sort_filter_elements(struct ndb_filter *filter,
 				 struct ndb_filter_elements *els,
 				 int (*cmp)(const void *, const void *))
 {
 	int i;
 
 	assert(ndb_filter_elem_is_ptr(&els->field));
 
 	for (i = 0; i < els->count; i++)
 		els->elements[i] += (uint64_t)filter->data_buf.start;
 
 	qsort(&els->elements[0], els->count, sizeof(els->elements[0]), cmp);
 
 	for (i = 0; i < els->count; i++)
 		els->elements[i] -= (uint64_t)filter->data_buf.start;
 }
 
 static int ndb_filter_field_eq(struct ndb_filter *a_filt,
 			       struct ndb_filter_elements *a_field,
 			       struct ndb_filter *b_filt,
 			       struct ndb_filter_elements *b_field)
 {
 	int i;
 	const char *a_str, *b_str;
 	unsigned char *a_id, *b_id;
 	uint64_t a_int, b_int;
 
 	if (a_field->count != b_field->count)
 		return 0;
 
 	if (a_field->field.type != b_field->field.type) {
 		ndb_debug("UNUSUAL: field types do not match in ndb_filter_field_eq\n");
 		return 0;
 	}
 
 	if (a_field->field.elem_type != b_field->field.elem_type) {
 		ndb_debug("UNUSUAL: field element types do not match in ndb_filter_field_eq\n");
 		return 0;
 	}
 
 	if (a_field->field.elem_type == NDB_ELEMENT_UNKNOWN) {
 		ndb_debug("UNUSUAL: field element types are unknown\n");
 		return 0;
 	}
 
 	for (i = 0; i < a_field->count; i++) {
 		switch (a_field->field.elem_type) {
 		case NDB_ELEMENT_UNKNOWN:
 			return 0;
 		case NDB_ELEMENT_STRING:
 			a_str = ndb_filter_get_string_element(a_filt, a_field, i);
 			b_str = ndb_filter_get_string_element(b_filt, b_field, i);
 			if (strcmp(a_str, b_str))
 				return 0;
 			break;
 		case NDB_ELEMENT_ID:
 			a_id = ndb_filter_get_id_element(a_filt, a_field, i);
 			b_id = ndb_filter_get_id_element(b_filt, b_field, i);
 			if (memcmp(a_id, b_id, 32))
 				return 0;
 			break;
 		case NDB_ELEMENT_INT:
 			a_int = ndb_filter_get_int_element(a_field, i);
 			b_int = ndb_filter_get_int_element(b_field, i);
 			if (a_int != b_int)
 				return 0;
 			break;
 		}
 	}
 
 	return 1;
 }
 
 void ndb_filter_end_field(struct ndb_filter *filter)
 {
 	int cur_offset;
 	struct ndb_filter_elements *cur;
 
 	cur_offset = filter->current;
 
 	if (!(cur = ndb_filter_current_element(filter)))
 		return;
 
 	filter->elements[filter->num_elements++] = cur_offset;
 
 	// sort elements for binary search
 	switch (cur->field.type) {
 	case NDB_FILTER_IDS:
 	case NDB_FILTER_AUTHORS:
 		sort_filter_elements(filter, cur, compare_ids);
 		break;
 	case NDB_FILTER_KINDS:
 		qsort(&cur->elements[0], cur->count,
 		      sizeof(cur->elements[0]), compare_kinds);
 		break;
 	case NDB_FILTER_TAGS:
 		// TODO: generic tag search sorting
 		break;
 	case NDB_FILTER_SINCE:
 	case NDB_FILTER_UNTIL:
 	case NDB_FILTER_LIMIT:
 	case NDB_FILTER_SEARCH:
 		// don't need to sort these
 		break;
 	}
 
 	filter->current = -1;
 
 }
 
 static void ndb_filter_group_init(struct ndb_filter_group *group)
 {
 	group->num_filters = 0;
 }
 
 static int ndb_filter_group_add(struct ndb_filter_group *group,
 				struct ndb_filter *filter)
 {
 	if (group->num_filters + 1 > MAX_FILTERS)
 		return 0;
 
 	return ndb_filter_clone(&group->filters[group->num_filters++], filter);
 }
 
 static int ndb_filter_group_matches(struct ndb_filter_group *group,
 				    struct ndb_note *note)
 {
 	int i;
 	struct ndb_filter *filter;
 
 	if (group->num_filters == 0)
 		return 1;
 
 	for (i = 0; i < group->num_filters; i++) {
 		filter = &group->filters[i];
 
 		if (ndb_filter_matches(filter, note))
 			return 1;
 	}
 
 	return 0;
 }
 
 static void ndb_make_search_key(struct ndb_search_key *key, unsigned char *id,
 			        uint64_t timestamp, const char *search)
 {
 	memcpy(key->id, id, 32);
 	key->timestamp = timestamp;
 	lowercase_strncpy(key->search, search, sizeof(key->search) - 1);
 	key->search[sizeof(key->search) - 1] = '\0';
 }
 
 static int ndb_write_profile_search_index(struct ndb_txn *txn,
 					  struct ndb_search_key *index_key,
 					  uint64_t profile_key)
 {
 	int rc;
 	MDB_val key, val;
 
 	key.mv_data = index_key;
 	key.mv_size = sizeof(*index_key);
 	val.mv_data = &profile_key;
 	val.mv_size = sizeof(profile_key);
 
 	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_PROFILE_SEARCH],
 			  &key, &val, 0)))
 	{
 		ndb_debug("ndb_write_profile_search_index failed: %s\n",
 			  mdb_strerror(rc));
 		return 0;
 	}
 
 	return 1;
 }
 
 
 // map usernames and display names to profile keys for user searching
 static int ndb_write_profile_search_indices(struct ndb_txn *txn,
 					    struct ndb_note *note,
 					    uint64_t profile_key,
 					    void *profile_root)
 {
 	struct ndb_search_key index;
 	NdbProfileRecord_table_t profile_record;
 	NdbProfile_table_t profile;
 
 	profile_record = NdbProfileRecord_as_root(profile_root);
 	profile = NdbProfileRecord_profile_get(profile_record);
 
 	const char *name = NdbProfile_name_get(profile);
 	const char *display_name = NdbProfile_display_name_get(profile);
 
 	// words + pubkey + created
 	if (name) {
 		ndb_make_search_key(&index, note->pubkey, note->created_at,
 				    name);
 		if (!ndb_write_profile_search_index(txn, &index, profile_key))
 			return 0;
 	}
 
 	if (display_name) {
 		// don't write the same name/display_name twice
 		if (name && !strcmp(display_name, name)) {
 			return 1;
 		}
 		ndb_make_search_key(&index, note->pubkey, note->created_at,
 				    display_name);
 		if (!ndb_write_profile_search_index(txn, &index, profile_key))
 			return 0;
 	}
 
 	return 1;
 }
 
 static inline void ndb_tsid_init(struct ndb_tsid *key, unsigned char *id,
 				 uint64_t timestamp)
 {
 	memcpy(key->id, id, 32);
 	key->timestamp = timestamp;
 }
 
 static inline void ndb_tsid_low(struct ndb_tsid *key, unsigned char *id)
 {
 	memcpy(key->id, id, 32);
 	key->timestamp = 0;
 }
 
 static inline void ndb_u64_ts_init(struct ndb_u64_ts *key, uint64_t integer,
 				     uint64_t timestamp)
 {
 	key->u64 = integer;
 	key->timestamp = timestamp;
 }
 
 // useful for range-searching for the latest key with a clustered created_at timen
 static inline void ndb_tsid_high(struct ndb_tsid *key, const unsigned char *id)
 {
 	memcpy(key->id, id, 32);
 	key->timestamp = UINT64_MAX;
 }
 
 static int _ndb_begin_query(struct ndb *ndb, struct ndb_txn *txn, int flags)
 {
 	txn->lmdb = &ndb->lmdb;
 	MDB_txn **mdb_txn = (MDB_txn **)&txn->mdb_txn;
 	if (!txn->lmdb->env)
 		return 0;
 	return mdb_txn_begin(txn->lmdb->env, NULL, flags, mdb_txn) == 0;
 }
 
 int ndb_begin_query(struct ndb *ndb, struct ndb_txn *txn)
 {
 	return _ndb_begin_query(ndb, txn, MDB_RDONLY);
 }
 
 // this should only be used in migrations, etc
 static int ndb_begin_rw_query(struct ndb *ndb, struct ndb_txn *txn)
 {
 	return _ndb_begin_query(ndb, txn, 0);
 }
 
 static int ndb_db_is_index(enum ndb_dbs index)
 {
 	switch (index) {
 		case NDB_DB_NOTE:
 		case NDB_DB_META:
 		case NDB_DB_PROFILE:
 		case NDB_DB_NOTE_ID:
 		case NDB_DB_NDB_META:
 		case NDB_DB_PROFILE_SEARCH:
 		case NDB_DB_PROFILE_LAST_FETCH:
 		case NDB_DB_NOTE_RELAYS:
 		case NDB_DBS:
 			return 0;
 		case NDB_DB_PROFILE_PK:
 		case NDB_DB_NOTE_KIND:
 		case NDB_DB_NOTE_TEXT:
 		case NDB_DB_NOTE_BLOCKS:
 		case NDB_DB_NOTE_TAGS:
 		case NDB_DB_NOTE_PUBKEY:
 		case NDB_DB_NOTE_PUBKEY_KIND:
 		case NDB_DB_NOTE_RELAY_KIND:
 			return 1;
 	}
 
 	return 0;
 }
 
 static inline void ndb_id_u64_ts_init(struct ndb_id_u64_ts *key,
 				      unsigned char *id, uint64_t iu64,
 				      uint64_t timestamp)
 {
 	memcpy(key->id, id, 32);
 	key->u64 = iu64;
 	key->timestamp = timestamp;
 }
 
 // formats the relay url buffer for the NDB_DB_NOTE_RELAYS value. It's a
 // null terminated string padded to 8 bytes (we must keep the entire database
 // aligned to 8 bytes at all times)
 static int prepare_relay_buf(char *relay_buf, int bufsize, const char *relay,
 			     int relay_len)
 {
 	struct cursor cur;
 
 	// make sure the size of the buffer is aligned
 	assert((bufsize % 8) == 0);
 
 	make_cursor((unsigned char *)relay_buf, (unsigned char *)relay_buf + bufsize, &cur);
 
 	// push the relay string
 	if (!cursor_push(&cur, (unsigned char *)relay, relay_len))
 		return 0;
 
 	// relay urls are null terminated for convenience
 	if (!cursor_push_byte(&cur, 0))
 		return 0;
 
 	// align the buffer
 	if (!cursor_align(&cur, 8))
 		return 0;
 
 	return cur.p - cur.start;
 }
 
 // Write to the note_id -> relay_url database. This records where notes
 // have been seen
 static int ndb_write_note_relay(struct ndb_txn *txn, uint64_t note_key,
 				const char *relay, int relay_len)
 {
 	char relay_buf[256];
 	int rc, len;
 	MDB_val k, v;
 
 	if (relay == NULL || relay_len == 0)
 		return 0;
 
 	if (!(len = prepare_relay_buf(relay_buf, sizeof(relay_buf), relay, relay_len))) {
 		fprintf(stderr, "relay url '%s' too large when writing note relay index\n", relay);
 		return 0;
 	}
 
 	assert((len % 8) == 0);
 
 	k.mv_data = &note_key;
 	k.mv_size = sizeof(note_key);
 
 	v.mv_data = relay_buf;
 	v.mv_size = len;
 
 	// NODUPDATA is specified so that we don't accidently add duplicate
 	// key/value pairs
 	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_RELAYS],
 			  &k, &v, MDB_NODUPDATA)))
 	{
 		ndb_debug("ndb_write_note_relay failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 
 	return 1;
 }
 
 static int ndb_write_note_relay_kind_index(struct ndb_txn *txn,
 					   uint64_t kind,
 					   uint64_t note_key,
 					   uint64_t created_at,
 					   const char *relay,
 					   int relay_len)
 {
 	// The relay kind key has a layout like so 
 	//
 	// - note_key:       00 + 8 bytes
 	// - kind:           08 + 8 bytes
 	// - created_at:     16 + 8 bytes
 	// - relay_url_size: 24 + 1 byte
 	// - relay_url:      25 + n byte null-terminated string
 	// - pad to 8 byte alignment
 
 	unsigned char buf[256];
 	int rc;
 	struct cursor cur;
 	MDB_val k, v;
 
 	// come on bro
 	if (relay_len > 248)
 		return 0;
 
 	if (relay == NULL || relay_len == 0)
 		return 0;
 
 	make_cursor(buf, buf + sizeof(buf), &cur);
 
 	if (!cursor_push(&cur, (unsigned char *)&note_key, 8))   return 0;
 	if (!cursor_push(&cur, (unsigned char *)&kind, 8))       return 0;
 	if (!cursor_push(&cur, (unsigned char *)&created_at, 8)) return 0;
 	if (!cursor_push_byte(&cur, (uint8_t)relay_len)) return 0;
 	if (!cursor_push(&cur, (unsigned char *)relay, relay_len)) return 0;
 	if (!cursor_align(&cur, 8)) return 0;
 
 	assert(((cur.p-cur.start)%8) == 0);
 
 	k.mv_data = cur.start;
 	k.mv_size = cur.p - cur.start;
 
 	v.mv_data = NULL;
 	v.mv_size = 0;
 
 	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_RELAY_KIND], &k, &v, 0))) {
 		fprintf(stderr, "write note relay kind index failed: %s\n",
 			  mdb_strerror(rc));
 		return 0;
 	}
 
 	return 1;
 }
 
 static int ndb_write_note_pubkey_index(struct ndb_txn *txn, struct ndb_note *note,
 				       uint64_t note_key)
 {
 	int rc;
 	struct ndb_tsid key;
 	MDB_val k, v;
 
 	ndb_tsid_init(&key, ndb_note_pubkey(note), ndb_note_created_at(note));
 
 	k.mv_data = &key;
 	k.mv_size = sizeof(key);
 
 	v.mv_data = &note_key;
 	v.mv_size = sizeof(note_key);
 
 	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_PUBKEY], &k, &v, 0))) {
 		fprintf(stderr, "write note pubkey index failed: %s\n",
 			  mdb_strerror(rc));
 		return 0;
 	}
 
 	return 1;
 }
 
 static int ndb_write_note_pubkey_kind_index(struct ndb_txn *txn,
 					    struct ndb_note *note,
 					    uint64_t note_key)
 {
 	int rc;
 	struct ndb_id_u64_ts key;
 	MDB_val k, v;
 
 	ndb_id_u64_ts_init(&key, ndb_note_pubkey(note), ndb_note_kind(note),
 			   ndb_note_created_at(note));
 
 	k.mv_data = &key;
 	k.mv_size = sizeof(key);
 
 	v.mv_data = &note_key;
 	v.mv_size = sizeof(note_key);
 
 	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_PUBKEY_KIND], &k, &v, 0))) {
 		fprintf(stderr, "write note pubkey_kind index failed: %s\n",
 			  mdb_strerror(rc));
 		return 0;
 	}
 
 	return 1;
 }
 
 
 static int ndb_rebuild_note_indices(struct ndb_txn *txn, enum ndb_dbs *indices, int num_indices)
 {
 	MDB_val k, v;
 	MDB_cursor *cur;
 	int i, drop_dbi, count, rc;
 	uint64_t note_key;
 	struct ndb_note *note;
 	enum ndb_dbs index;
 
 	// 0 means empty, not delete the dbi
 	drop_dbi = 0;
 
 	// ensure they are all index dbs
 	for (i = 0; i < num_indices; i++) {
 		if (!ndb_db_is_index(indices[i])) {
 			fprintf(stderr, "ndb_rebuild_note_index: %s is not an index db\n", ndb_db_name(indices[i]));
 			return -1;
 		}
 	}
 
 	// empty the index dbs before we rebuild
 	for (i = 0; i < num_indices; i++) {
 		index = indices[i];
 		if (mdb_drop(txn->mdb_txn, index, drop_dbi)) {
 			fprintf(stderr, "ndb_rebuild_pubkey_index: mdb_drop failed for %s\n", ndb_db_name(index));
 			return -1;
 		}
 	}
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE], &cur))) {
 		fprintf(stderr, "ndb_migrate_user_search_indices: mdb_cursor_open failed, error %d\n", rc);
 		return -1;
 	}
 
 	count = 0;
 
 	// loop through all notes and write search indices
 	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
 		note = v.mv_data;
 		note_key = *((uint64_t*)k.mv_data);
 
 		for (i = 0; i < num_indices; i++) {
 			index = indices[i];
 			switch (index) {
 			case NDB_DB_NOTE:
 			case NDB_DB_META:
 			case NDB_DB_PROFILE:
 			case NDB_DB_NOTE_ID:
 			case NDB_DB_NDB_META:
 			case NDB_DB_PROFILE_SEARCH:
 			case NDB_DB_PROFILE_LAST_FETCH:
 			case NDB_DB_NOTE_RELAYS:
 			case NDB_DBS:
 				// this should never happen since we check at
 				// the start
 				count = -1;
 				goto cleanup;
 			case NDB_DB_PROFILE_PK:
 			case NDB_DB_NOTE_KIND:
 			case NDB_DB_NOTE_TEXT:
 			case NDB_DB_NOTE_BLOCKS:
 			case NDB_DB_NOTE_TAGS:
 				fprintf(stderr, "%s index rebuild not supported yet. sorry.\n", ndb_db_name(index));
 				count = -1;
 				goto cleanup;
 			case NDB_DB_NOTE_PUBKEY:
 				if (!ndb_write_note_pubkey_index(txn, note, note_key)) {
 					count = -1;
 					goto cleanup;
 				}
 				break;
 			case NDB_DB_NOTE_RELAY_KIND:
 				fprintf(stderr, "it doesn't make sense to rebuild note relay kind index\n");
 				return 0;
 			case NDB_DB_NOTE_PUBKEY_KIND:
 				if (!ndb_write_note_pubkey_kind_index(txn, note, note_key)) {
 					count = -1;
 					goto cleanup;
 				}
 				break;
 			}
 		}
 
 		count++;
 	}
 
 cleanup:
 	mdb_cursor_close(cur);
 
 	return count;
 }
 
 
 // Migrations
 //
 
 // This was before we had note_profile_pubkey{,_kind} indices. Let's create them.
 static int ndb_migrate_profile_indices(struct ndb_txn *txn)
 {
 	int count;
 
 	enum ndb_dbs indices[] = {NDB_DB_NOTE_PUBKEY, NDB_DB_NOTE_PUBKEY_KIND};
 	if ((count = ndb_rebuild_note_indices(txn, indices, 2)) != -1) {
 		fprintf(stderr, "migrated %d notes to have pubkey and pubkey_kind indices\n", count);
 		return 1;
 	} else {
 		fprintf(stderr, "error migrating notes to have pubkey and pubkey_kind indices, aborting.\n");
 		return 0;
 	}
 }
 
 static int ndb_migrate_user_search_indices(struct ndb_txn *txn)
 {
 	int rc;
 	MDB_cursor *cur;
 	MDB_val k, v;
 	void *profile_root;
 	NdbProfileRecord_table_t record;
 	struct ndb_note *note;
 	uint64_t note_key, profile_key;
 	size_t len;
 	int count;
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_PROFILE], &cur))) {
 		fprintf(stderr, "ndb_migrate_user_search_indices: mdb_cursor_open failed, error %d\n", rc);
 		return 0;
 	}
 
 	count = 0;
 
 	// loop through all profiles and write search indices
 	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
 		profile_root = v.mv_data;
 		profile_key = *((uint64_t*)k.mv_data);
 		record = NdbProfileRecord_as_root(profile_root);
 		note_key = NdbProfileRecord_note_key(record);
 		note = ndb_get_note_by_key(txn, note_key, &len);
 
 		if (note == NULL) {
 			continue;
 		}
 
 		if (!ndb_write_profile_search_indices(txn, note, profile_key,
 						      profile_root)) {
 			fprintf(stderr, "ndb_migrate_user_search_indices: ndb_write_profile_search_indices failed\n");
 			continue;
 		}
 
 		count++;
 	}
 
 	fprintf(stderr, "migrated %d profiles to include search indices\n", count);
 
 	mdb_cursor_close(cur);
 
 	return 1;
 }
 
 static int ndb_migrate_lower_user_search_indices(struct ndb_txn *txn)
 {
 	// just drop the search db so we can rebuild it
 	if (mdb_drop(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_PROFILE_SEARCH], 0)) {
 		fprintf(stderr, "ndb_migrate_lower_user_search_indices: mdb_drop failed\n");
 		return 0;
 	}
 
 	return ndb_migrate_user_search_indices(txn);
 }
 
 int ndb_process_profile_note(struct ndb_note *note, struct ndb_profile_record_builder *profile);
 
 
 int ndb_db_version(struct ndb_txn *txn)
 {
 	uint64_t version, version_key;
 	MDB_val k, v;
 
 	version_key = NDB_META_KEY_VERSION;
 	k.mv_data = &version_key;
 	k.mv_size = sizeof(version_key);
 
 	if (mdb_get(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NDB_META], &k, &v)) {
 		version = -1;
 	} else {
 		if (v.mv_size != 8) {
 			fprintf(stderr, "run_migrations: invalid version size?");
 			return 0;
 		}
 		version = *((uint64_t*)v.mv_data);
 	}
 
 	return version;
 }
 
 // custom pubkey+kind+timestamp comparison function. This is used by lmdb to
 // perform b+ tree searches over the pubkey+kind+timestamp index
 static int ndb_id_u64_ts_compare(const MDB_val *a, const MDB_val *b)
 {
 	struct ndb_id_u64_ts *tsa, *tsb;
 	MDB_val a2 = *a, b2 = *b;
 
 	a2.mv_size = sizeof(tsa->id);
 	b2.mv_size = sizeof(tsb->id);
 
 	int cmp = mdb_cmp_memn(&a2, &b2);
 	if (cmp) return cmp;
 
 	tsa = a->mv_data;
 	tsb = b->mv_data;
 
 	if (tsa->u64 < tsb->u64)
 		return -1;
 	else if (tsa->u64 > tsb->u64)
 		return 1;
 
 	if (tsa->timestamp < tsb->timestamp)
 		return -1;
 	else if (tsa->timestamp > tsb->timestamp)
 		return 1;
 
 	return 0;
 }
 
 // custom kind+timestamp comparison function. This is used by lmdb to perform
 // b+ tree searches over the kind+timestamp index
 static int ndb_u64_ts_compare(const MDB_val *a, const MDB_val *b)
 {
 	struct ndb_u64_ts *tsa, *tsb;
 	tsa = a->mv_data;
 	tsb = b->mv_data;
 
 	if (tsa->u64 < tsb->u64)
 		return -1;
 	else if (tsa->u64 > tsb->u64)
 		return 1;
 
 	if (tsa->timestamp < tsb->timestamp)
 		return -1;
 	else if (tsa->timestamp > tsb->timestamp)
 		return 1;
 
 	return 0;
 }
 
 static int ndb_tsid_compare(const MDB_val *a, const MDB_val *b)
 {
 	struct ndb_tsid *tsa, *tsb;
 	MDB_val a2 = *a, b2 = *b;
 
 	a2.mv_size = sizeof(tsa->id);
 	b2.mv_size = sizeof(tsb->id);
 
 	int cmp = mdb_cmp_memn(&a2, &b2);
 	if (cmp) return cmp;
 
 	tsa = a->mv_data;
 	tsb = b->mv_data;
 
 	if (tsa->timestamp < tsb->timestamp)
 		return -1;
 	else if (tsa->timestamp > tsb->timestamp)
 		return 1;
 	return 0;
 }
 
 enum ndb_ingester_msgtype {
 	NDB_INGEST_EVENT, // write json to the ingester queue for processing
 	NDB_INGEST_QUIT,  // kill ingester thread immediately
 };
 
 struct ndb_ingester_event {
 	const char *relay;
 	char *json;
 	unsigned client : 1; // ["EVENT", {...}] messages
 	unsigned len : 31;
 };
 
 struct ndb_writer_note_relay {
 	const char *relay;
 	uint64_t note_key;
 	uint64_t kind;
 	uint64_t created_at;
 };
 
 struct ndb_writer_note {
 	struct ndb_note *note;
 	size_t note_len;
 	const char *relay;
 };
 
 struct ndb_writer_profile {
 	struct ndb_writer_note note;
 	struct ndb_profile_record_builder record;
 };
 
 struct ndb_ingester_msg {
 	enum ndb_ingester_msgtype type;
 	union {
 		struct ndb_ingester_event event;
 	};
 };
 
 struct ndb_writer_ndb_meta {
 	// these are 64 bit because I'm paranoid of db-wide alignment issues
 	uint64_t version;
 };
 
 // Used in the writer thread when writing ndb_profile_fetch_record's
 //   kv = pubkey: recor
 struct ndb_writer_last_fetch {
 	unsigned char pubkey[32];
 	uint64_t fetched_at;
 };
 
 // write note blocks
 struct ndb_writer_blocks {
 	struct ndb_blocks *blocks;
 	uint64_t note_key;
 };
 
 // The different types of messages that the writer thread can write to the
 // database
 struct ndb_writer_msg {
 	enum ndb_writer_msgtype type;
 	union {
 		struct ndb_writer_note_relay note_relay;
 		struct ndb_writer_note note;
 		struct ndb_writer_profile profile;
 		struct ndb_writer_ndb_meta ndb_meta;
 		struct ndb_writer_last_fetch last_fetch;
 		struct ndb_writer_blocks blocks;
 	};
 };
 
 static inline int ndb_writer_queue_msg(struct ndb_writer *writer,
 				       struct ndb_writer_msg *msg)
 {
 	return prot_queue_push(&writer->inbox, msg);
 }
 
 static uint64_t ndb_write_note_and_profile(struct ndb_txn *txn, struct ndb_writer_profile *profile, unsigned char *scratch, size_t scratch_size, uint32_t ndb_flags);
 static int ndb_migrate_utf8_profile_names(struct ndb_txn *txn)
 {
 	int rc;
 	MDB_cursor *cur;
 	MDB_val k, v;
 	void *profile_root;
 	NdbProfileRecord_table_t record;
 	struct ndb_note *note, *copied_note;
 	uint64_t note_key;
 	size_t len;
 	int count, failed, ret;
 	struct ndb_writer_profile profile;
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_PROFILE], &cur))) {
 		fprintf(stderr, "ndb_migrate_utf8_profile_names: mdb_cursor_open failed, error %d\n", rc);
 		return 0;
 	}
 
 	size_t scratch_size = 8 * 1024 * 1024;
 	unsigned char *scratch = malloc(scratch_size);
 
 	ret = 1;
 	count = 0;
 	failed = 0;
 
 	// loop through all profiles and write search indices
 	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
 		profile_root = v.mv_data;
 		record = NdbProfileRecord_as_root(profile_root);
 		note_key = NdbProfileRecord_note_key(record);
 		note = ndb_get_note_by_key(txn, note_key, &len);
 
 		if (note == NULL) {
 			failed++;
 			continue;
 		}
 
 		struct ndb_profile_record_builder *b = &profile.record;
 
 		// reprocess profile
 		if (!ndb_process_profile_note(note, b)) {
 			failed++;
 			continue;
 		}
 
 		// the writer needs to own this note, and its expected to free it
 		copied_note = malloc(len);
 		memcpy(copied_note, note, len);
 
 		profile.note.note = copied_note;
 		profile.note.note_len = len;
 
 		// we don't pass in flags when migrating... a bit sketchy but
 		// whatever. noone is using this to customize nostrdb atm
 		if (ndb_write_note_and_profile(txn, &profile, scratch, scratch_size, 0)) {
 			count++;
 		}
 	}
 
 	fprintf(stderr, "migrated %d profiles to fix utf8 profile names\n", count);
 
 	if (failed != 0) {
 		fprintf(stderr, "failed to migrate %d profiles to fix utf8 profile names\n", failed);
 	}
 
 	free(scratch);
 	mdb_cursor_close(cur);
 
 	return ret;
 }
 
 static struct ndb_migration MIGRATIONS[] = {
 	{ .fn = ndb_migrate_user_search_indices },
 	{ .fn = ndb_migrate_lower_user_search_indices },
 	{ .fn = ndb_migrate_utf8_profile_names },
 	{ .fn = ndb_migrate_profile_indices },
 };
 
 
 int ndb_end_query(struct ndb_txn *txn)
 {
 	// this works on read or write queries.
 	return mdb_txn_commit(txn->mdb_txn) == 0;
 }
 
 int ndb_note_verify(void *ctx, unsigned char pubkey[32], unsigned char id[32],
 		    unsigned char sig[64])
 {
 	secp256k1_xonly_pubkey xonly_pubkey;
 	int ok;
 
 	ok = secp256k1_xonly_pubkey_parse((secp256k1_context*)ctx, &xonly_pubkey,
 					  pubkey) != 0;
 	if (!ok) return 0;
 
 	ok = secp256k1_schnorrsig_verify((secp256k1_context*)ctx, sig, id, 32,
 					 &xonly_pubkey) > 0;
 	if (!ok) return 0;
 
 	return 1;
 }
 
 static void ndb_writer_last_profile_fetch(struct ndb_txn *txn,
 					  const unsigned char *pubkey,
 					  uint64_t fetched_at)
 {
 	int rc;
 	MDB_val key, val;
 
 	key.mv_data = (unsigned char*)pubkey;
 	key.mv_size = 32;
 	val.mv_data = &fetched_at;
 	val.mv_size = sizeof(fetched_at);
 
 	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_PROFILE_LAST_FETCH],
 			  &key, &val, 0)))
 	{
 		ndb_debug("write version to ndb_meta failed: %s\n",
 				mdb_strerror(rc));
 		return;
 	}
 
 	//fprintf(stderr, "writing version %" PRIu64 "\n", version);
 }
 
 
 // We just received a profile that we haven't processed yet, but it could
 // be an older one! Make sure we only write last fetched profile if it's a new
 // one
 //
 // To do this, we first check the latest profile in the database. If the
 // created_date for this profile note is newer, then we write a
 // last_profile_fetch record, otherwise we do not.
 //
 // WARNING: This function is only valid when called from the writer thread
 static int ndb_maybe_write_last_profile_fetch(struct ndb_txn *txn,
 					       struct ndb_note *note)
 {
 	size_t len;
 	uint64_t profile_key, note_key;
 	void *root;
 	struct ndb_note *last_profile;
 	NdbProfileRecord_table_t record;
 
 	if ((root = ndb_get_profile_by_pubkey(txn, note->pubkey, &len, &profile_key))) {
 		record = NdbProfileRecord_as_root(root);
 		note_key = NdbProfileRecord_note_key(record);
 		last_profile = ndb_get_note_by_key(txn, note_key, &len);
 		if (last_profile == NULL) {
 			return 0;
 		}
 
 		// found profile, let's see if it's newer than ours
 		if (note->created_at > last_profile->created_at) {
 			// this is a new profile note, record last fetched time
 			ndb_writer_last_profile_fetch(txn, note->pubkey, time(NULL));
 		}
 	} else {
 		// couldn't fetch profile. record last fetched time
 		ndb_writer_last_profile_fetch(txn, note->pubkey, time(NULL));
 	}
 
 	return 1;
 }
 
 int ndb_write_last_profile_fetch(struct ndb *ndb, const unsigned char *pubkey,
 				 uint64_t fetched_at)
 {
 	struct ndb_writer_msg msg;
 	msg.type = NDB_WRITER_PROFILE_LAST_FETCH;
 	memcpy(&msg.last_fetch.pubkey[0], pubkey, 32);
 	msg.last_fetch.fetched_at = fetched_at;
 
 	return ndb_writer_queue_msg(&ndb->writer, &msg);
 }
 
 
 // When doing cursor scans from greatest to lowest, this function positions the
 // cursor at the first element before descending. MDB_SET_RANGE puts us right
 // after the first element, so we have to go back one.
 static int ndb_cursor_start(MDB_cursor *cur, MDB_val *k, MDB_val *v)
 {
 	// Position cursor at the next key greater than or equal to the
 	// specified key
 	if (mdb_cursor_get(cur, k, v, MDB_SET_RANGE)) {
 		// Failed :(. It could be the last element?
 		if (mdb_cursor_get(cur, k, v, MDB_LAST))
 			return 0;
 	} else {
 		// if set range worked and our key exists, it should be
 		// the one right before this one
 		if (mdb_cursor_get(cur, k, v, MDB_PREV))
 			return 0;
 	}
 
 	return 1;
 }
 
 
 // get some value based on a clustered id key
 int ndb_get_tsid(struct ndb_txn *txn, enum ndb_dbs db, const unsigned char *id,
 		 MDB_val *val)
 {
 	MDB_val k, v;
 	MDB_cursor *cur;
 	int success = 0, rc;
 	struct ndb_tsid tsid;
 
 	// position at the most recent
 	ndb_tsid_high(&tsid, id);
 
 	k.mv_data = &tsid;
 	k.mv_size = sizeof(tsid);
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[db], &cur))) {
 		ndb_debug("ndb_get_tsid: failed to open cursor: '%s'\n", mdb_strerror(rc));
 		return 0;
 	}
 
 	if (!ndb_cursor_start(cur, &k, &v))
 		goto cleanup;
 
 	if (memcmp(k.mv_data, id, 32) == 0) {
 		*val = v;
 		success = 1;
 	}
 
 cleanup:
 	mdb_cursor_close(cur);
 	return success;
 }
 
 static void *ndb_lookup_by_key(struct ndb_txn *txn, uint64_t key,
 			       enum ndb_dbs store, size_t *len)
 {
 	MDB_val k, v;
 
 	k.mv_data = &key;
 	k.mv_size = sizeof(key);
 
 	if (mdb_get(txn->mdb_txn, txn->lmdb->dbs[store], &k, &v)) {
 		ndb_debug("ndb_lookup_by_key: mdb_get note failed\n");
 		return NULL;
 	}
 
 	if (len)
 		*len = v.mv_size;
 
 	return v.mv_data;
 }
 
 static void *ndb_lookup_tsid(struct ndb_txn *txn, enum ndb_dbs ind,
 			     enum ndb_dbs store, const unsigned char *pk,
 			     size_t *len, uint64_t *primkey)
 {
 	MDB_val k, v;
 	void *res = NULL;
 	if (len)
 		*len = 0;
 
 	if (!ndb_get_tsid(txn, ind, pk, &k)) {
 		//ndb_debug("ndb_get_profile_by_pubkey: ndb_get_tsid failed\n");
 		return 0;
 	}
 
 	if (primkey)
 		*primkey = *(uint64_t*)k.mv_data;
 
 	if (mdb_get(txn->mdb_txn, txn->lmdb->dbs[store], &k, &v)) {
 		ndb_debug("ndb_get_profile_by_pubkey: mdb_get note failed\n");
 		return 0;
 	}
 
 	res = v.mv_data;
 	assert(((uint64_t)res % 4) == 0);
 	if (len)
 		*len = v.mv_size;
 	return res;
 }
 
 void *ndb_get_profile_by_pubkey(struct ndb_txn *txn, const unsigned char *pk, size_t *len, uint64_t *key)
 {
 	return ndb_lookup_tsid(txn, NDB_DB_PROFILE_PK, NDB_DB_PROFILE, pk, len, key);
 }
 
 struct ndb_note *ndb_get_note_by_id(struct ndb_txn *txn, const unsigned char *id, size_t *len, uint64_t *key)
 {
 	return ndb_lookup_tsid(txn, NDB_DB_NOTE_ID, NDB_DB_NOTE, id, len, key);
 }
 
 static inline uint64_t ndb_get_indexkey_by_id(struct ndb_txn *txn,
 					      enum ndb_dbs db,
 					      const unsigned char *id)
 {
 	MDB_val k;
 
 	if (!ndb_get_tsid(txn, db, id, &k))
 		return 0;
 
 	return *(uint32_t*)k.mv_data;
 }
 
 uint64_t ndb_get_notekey_by_id(struct ndb_txn *txn, const unsigned char *id)
 {
 	return ndb_get_indexkey_by_id(txn, NDB_DB_NOTE_ID, id);
 }
 
 uint64_t ndb_get_profilekey_by_pubkey(struct ndb_txn *txn, const unsigned char *id)
 {
 	return ndb_get_indexkey_by_id(txn, NDB_DB_PROFILE_PK, id);
 }
 
 struct ndb_note *ndb_get_note_by_key(struct ndb_txn *txn, uint64_t key, size_t *len)
 {
 	return ndb_lookup_by_key(txn, key, NDB_DB_NOTE, len);
 }
 
 void *ndb_get_profile_by_key(struct ndb_txn *txn, uint64_t key, size_t *len)
 {
 	return ndb_lookup_by_key(txn, key, NDB_DB_PROFILE, len);
 }
 
 uint64_t
 ndb_read_last_profile_fetch(struct ndb_txn *txn, const unsigned char *pubkey)
 {
 	MDB_val k, v;
 
 	k.mv_data = (unsigned char*)pubkey;
 	k.mv_size = 32;
 
 	if (mdb_get(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_PROFILE_LAST_FETCH], &k, &v)) {
 		//ndb_debug("ndb_read_last_profile_fetch: mdb_get note failed\n");
 		return 0;
 	}
 
 	return *((uint64_t*)v.mv_data);
 }
 
 
 static int ndb_has_note(struct ndb_txn *txn, const unsigned char *id)
 {
 	MDB_val val;
 
 	if (!ndb_get_tsid(txn, NDB_DB_NOTE_ID, id, &val))
 		return 0;
 
 	return 1;
 }
 
 static void ndb_txn_from_mdb(struct ndb_txn *txn, struct ndb_lmdb *lmdb,
 			     MDB_txn *mdb_txn)
 {
 	txn->lmdb = lmdb;
 	txn->mdb_txn = mdb_txn;
 }
 
 static enum ndb_idres ndb_ingester_json_controller(void *data, const char *hexid)
 {
 	unsigned char id[32];
 	struct ndb_ingest_controller *c = data;
 	struct ndb_txn txn;
 
 	hex_decode(hexid, 64, id, sizeof(id));
 
 	// let's see if we already have it
 	ndb_txn_from_mdb(&txn, c->lmdb, c->read_txn);
 	c->note = ndb_get_note_by_id(&txn, id, NULL, &c->note_key);
 
 	if (c->note == NULL)
 		return NDB_IDRES_CONT;
 
 	return NDB_IDRES_STOP;
 }
 
 static int ndbprofile_parse_json(flatcc_builder_t *B,
         const char *buf, size_t bufsiz, int flags, NdbProfile_ref_t *profile)
 {
 	flatcc_json_parser_t parser, *ctx = &parser;
 	flatcc_json_parser_init(ctx, B, buf, buf + bufsiz, flags);
 
 	if (flatcc_builder_start_buffer(B, 0, 0, 0))
 		return 0;
 
 	NdbProfile_parse_json_table(ctx, buf, buf + bufsiz, profile);
 	if (ctx->error)
 		return 0;
 
 	if (!flatcc_builder_end_buffer(B, *profile))
 		return 0;
 
 	ctx->end_loc = buf;
 
 
 	return 1;
 }
 
 void ndb_profile_record_builder_init(struct ndb_profile_record_builder *b)
 {
 	b->builder = malloc(sizeof(*b->builder));
 	b->flatbuf = NULL;
 }
 
 void ndb_profile_record_builder_free(struct ndb_profile_record_builder *b)
 {
 	if (b->builder)
 		free(b->builder);
 	if (b->flatbuf)
 		free(b->flatbuf);
 
 	b->builder = NULL;
 	b->flatbuf = NULL;
 }
 
 int ndb_process_profile_note(struct ndb_note *note,
 			     struct ndb_profile_record_builder *profile)
 {
 	int res;
 
 	NdbProfile_ref_t profile_table;
 	flatcc_builder_t *builder;
 
 	ndb_profile_record_builder_init(profile);
 	builder = profile->builder;
 	flatcc_builder_init(builder);
 
 	NdbProfileRecord_start_as_root(builder);
 
 	//printf("parsing profile '%.*s'\n", note->content_length, ndb_note_content(note));
 	if (!(res = ndbprofile_parse_json(builder, ndb_note_content(note),
 					  note->content_length,
 					  flatcc_json_parser_f_skip_unknown,
 					  &profile_table)))
 	{
 		ndb_debug("profile_parse_json failed %d '%.*s'\n", res,
 			  note->content_length, ndb_note_content(note));
 		ndb_profile_record_builder_free(profile);
 		return 0;
 	}
 
 	uint64_t received_at = time(NULL);
 	const char *lnurl = "fixme";
 
 	NdbProfileRecord_profile_add(builder, profile_table);
 	NdbProfileRecord_received_at_add(builder, received_at);
 
 	flatcc_builder_ref_t lnurl_off;
 	lnurl_off = flatcc_builder_create_string_str(builder, lnurl);
 
 	NdbProfileRecord_lnurl_add(builder, lnurl_off);
 
 	//*profile = flatcc_builder_finalize_aligned_buffer(builder, profile_len);
 	return 1;
 }
 
 static int ndb_ingester_queue_event(struct ndb_ingester *ingester,
 				    char *json, unsigned len,
 				    unsigned client, const char *relay)
 {
 	struct ndb_ingester_msg msg;
 	msg.type = NDB_INGEST_EVENT;
 
 	msg.event.json = json;
 	msg.event.len = len;
 	msg.event.client = client;
 	msg.event.relay = relay;
 
 	return threadpool_dispatch(&ingester->tp, &msg);
 }
 
 void ndb_ingest_meta_init(struct ndb_ingest_meta *meta, unsigned client, const char *relay)
 {
 	meta->client = client;
 	meta->relay = relay;
 }
 
 static int ndb_ingest_event(struct ndb_ingester *ingester, const char *json,
 			    int len, struct ndb_ingest_meta *meta)
 {
 	const char *relay = meta->relay;
 
 	// Without this, we get bus errors in the json parser inside when
 	// trying to ingest empty kind 6 reposts... we should probably do fuzz
 	// testing on inputs to the json parser
 	if (len == 0)
 		return 0;
 
 	// Since we need to return as soon as possible, and we're not
 	// making any assumptions about the lifetime of the string, we
 	// definitely need to copy the json here. In the future once we
 	// have our thread that manages a websocket connection, we can
 	// avoid the copy and just use the buffer we get from that
 	// thread.
 	char *json_copy = strdupn(json, len);
 	if (json_copy == NULL)
 		return 0;
 
 	if (relay != NULL) {
 		relay = strdup(meta->relay);
 		if (relay == NULL)
 			return 0;
 	}
 
 	return ndb_ingester_queue_event(ingester, json_copy, len, meta->client, relay);
 }
 
 
 static int ndb_ingester_process_note(secp256k1_context *ctx,
 				     struct ndb_note *note,
 				     size_t note_size,
 				     struct ndb_writer_msg *out,
 				     struct ndb_ingester *ingester,
 				     const char *relay)
 {
 	enum ndb_ingest_filter_action action;
 	struct ndb_ingest_meta meta;
 
 	action = NDB_INGEST_ACCEPT;
 
 	if (ingester->filter)
 		action = ingester->filter(ingester->filter_context, note);
 
 	if (action == NDB_INGEST_REJECT)
 		return 0;
 
 	// some special situations we might want to skip sig validation,
 	// like during large imports
 	if (action == NDB_INGEST_SKIP_VALIDATION || (ingester->flags & NDB_FLAG_SKIP_NOTE_VERIFY)) {
 		// if we're skipping validation we don't need to verify
 	} else {
 		// verify! If it's an invalid note we don't need to
 		// bother writing it to the database
 		if (!ndb_note_verify(ctx, note->pubkey, note->id, note->sig)) {
 			ndb_debug("signature verification failed\n");
 			return 0;
 		}
 	}
 
 	// we didn't find anything. let's send it
 	// to the writer thread
 	note = realloc(note, note_size);
 	assert(((uint64_t)note % 4) == 0);
 
 	if (note->kind == 0) {
 		struct ndb_profile_record_builder *b =
 			&out->profile.record;
 
 		ndb_process_profile_note(note, b);
 
 		out->type = NDB_WRITER_PROFILE;
 		out->profile.note.note = note;
 		out->profile.note.note_len = note_size;
 		return 1;
 	} else if (note->kind == 6) {
 		// process the repost if we have a repost event
 		ndb_debug("processing kind 6 repost\n");
 		// dup the relay string
 		ndb_ingest_meta_init(&meta, 0, relay);
 		ndb_ingest_event(ingester, ndb_note_content(note),
 					   ndb_note_content_length(note),
 					   &meta);
 	}
 
 	out->type = NDB_WRITER_NOTE;
 	out->note.note = note;
 	out->note.note_len = note_size;
 	out->note.relay = relay;
 
 	return 1;
 }
 
 int ndb_note_seen_on_relay(struct ndb_txn *txn, uint64_t note_key, const char *relay)
 {
 	MDB_val k, v;
 	MDB_cursor *cur;
 	int rc, len;
 	char relay_buf[256];
 
 	if (relay == NULL)
 		return 0;
 
 	len = strlen(relay);
 
 	if (!(len = prepare_relay_buf(relay_buf, sizeof(relay_buf), relay, len)))
 		return 0;
 
 	assert((len % 8) == 0);
 
 	k.mv_data = &note_key;
 	k.mv_size = sizeof(note_key);
 
 	v.mv_data = relay_buf;
 	v.mv_size = len;
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_RELAYS], &cur)) != MDB_SUCCESS)
 		return 0;
 
 	rc = mdb_cursor_get(cur, &k, &v, MDB_GET_BOTH);
 	mdb_cursor_close(cur);
 
 	return rc == MDB_SUCCESS;
 }
 
 // process the relay for the note. this is called when we already have the
 // note in the database but still need to check if the relay needs to be
 // written to the relay indexes for corresponding note
 static int ndb_process_note_relay(struct ndb_txn *txn, struct ndb_writer_msg *out,
 				  uint64_t note_key, struct ndb_note *note,
 				  const char *relay)
 {
 	// query to see if we already have the relay on this note
 	if (ndb_note_seen_on_relay(txn, note_key, relay)) {
 		return 0;
 	}
 
 	// if not, tell the writer thread to emit a NOTE_RELAY event
 	out->type = NDB_WRITER_NOTE_RELAY;
 
 	out->note_relay.relay = relay;
 	out->note_relay.note_key = note_key;
 	out->note_relay.kind = ndb_note_kind(note);
 	out->note_relay.created_at = ndb_note_created_at(note);
 
 	return 1;
 }
 
 static int ndb_ingester_process_event(secp256k1_context *ctx,
 				      struct ndb_ingester *ingester,
 				      struct ndb_ingester_event *ev,
 				      struct ndb_writer_msg *out,
 				      MDB_txn *read_txn)
 {
 	struct ndb_tce tce;
 	struct ndb_fce fce;
 	struct ndb_note *note;
 	struct ndb_ingest_controller controller;
 	struct ndb_id_cb cb;
 	void *buf;
 	int ok;
 	size_t bufsize, note_size;
 
 	ok = 0;
 
 	// we will use this to check if we already have it in the DB during
 	// ID parsing
 	controller.read_txn = read_txn;
 	controller.lmdb = ingester->lmdb;
 	cb.fn = ndb_ingester_json_controller;
 	cb.data = &controller;
 
 	// since we're going to be passing this allocated note to a different
 	// thread, we can't use thread-local buffers. just allocate a block
         bufsize = max(ev->len * 8.0, 4096);
 	buf = malloc(bufsize);
 	if (!buf) {
 		ndb_debug("couldn't malloc buf\n");
 		return 0;
 	}
 
 	note_size =
 		ev->client ?
 		ndb_client_event_from_json(ev->json, ev->len, &fce, buf, bufsize, &cb) :
 		ndb_ws_event_from_json(ev->json, ev->len, &tce, buf, bufsize, &cb);
 
 	// This is a result from our special json parser. It parsed the id
 	// and found that we already have it in the database
 	if ((int)note_size == -42) {
 		assert(controller.note != NULL);
 		assert(controller.note_key != 0);
 		struct ndb_txn txn;
 		ndb_txn_from_mdb(&txn, ingester->lmdb, read_txn);
 
 		// we still need to process the relays on the note even
 		// if we already have it
 	 	if (ev->relay && ndb_process_note_relay(&txn, out,
 							controller.note_key,
 							controller.note,
 							ev->relay))
 		{
 			// free note buf here since we don't pass the note to the writer thread
 			free(buf);
 			goto success;
 		} else {
 			// we already have the note and there are no new
 			// relays to process. nothing to write.
 			goto cleanup;
 		}
 	} else if (note_size == 0) {
 		ndb_debug("failed to parse '%.*s'\n", ev->len, ev->json);
 		goto cleanup;
 	}
 
 	//ndb_debug("parsed evtype:%d '%.*s'\n", tce.evtype, ev->len, ev->json);
 
 	if (ev->client) {
 		switch (fce.evtype) {
 		case NDB_FCE_EVENT:
 			note = fce.event.note;
 			if (note != buf) {
 				ndb_debug("note buffer not equal to malloc'd buffer\n");
 				goto cleanup;
 			}
 
 			if (!ndb_ingester_process_note(ctx, note, note_size,
 						       out, ingester,
 						       ev->relay)) {
 				ndb_debug("failed to process note\n");
 				goto cleanup;
 			} else {
 				goto success;
 			}
 		}
 	} else {
 		switch (tce.evtype) {
 		case NDB_TCE_AUTH:   goto cleanup;
 		case NDB_TCE_NOTICE: goto cleanup;
 		case NDB_TCE_EOSE:   goto cleanup;
 		case NDB_TCE_OK:     goto cleanup;
 		case NDB_TCE_EVENT:
 			note = tce.event.note;
 			if (note != buf) {
 				ndb_debug("note buffer not equal to malloc'd buffer\n");
 				goto cleanup;
 			}
 
 			if (!ndb_ingester_process_note(ctx, note, note_size,
 						       out, ingester,
 						       ev->relay)) {
 				ndb_debug("failed to process note\n");
 				goto cleanup;
 			} else {
 				goto success;
 			}
 		}
 	}
 
 
 success:
 	free(ev->json);
 	// we don't free relay or buf since those are passed to the writer thread
 	return 1;
 
 cleanup:
 	free(ev->json);
 	if (ev->relay)
 		free((void*)ev->relay);
 	free(buf);
 
 	return ok;
 }
 
 static uint64_t ndb_get_last_key(MDB_txn *txn, MDB_dbi db)
 {
 	MDB_cursor *mc;
 	MDB_val key, val;
 
 	if (mdb_cursor_open(txn, db, &mc))
 		return 0;
 
 	if (mdb_cursor_get(mc, &key, &val, MDB_LAST)) {
 		mdb_cursor_close(mc);
 		return 0;
 	}
 
 	mdb_cursor_close(mc);
 
 	assert(key.mv_size == 8);
         return *((uint64_t*)key.mv_data);
 }
 
 //
 // make a search key meant for user queries without any other note info
 static void ndb_make_search_key_low(struct ndb_search_key *key, const char *search)
 {
 	memset(key->id, 0, sizeof(key->id));
 	key->timestamp = 0;
 	lowercase_strncpy(key->search, search, sizeof(key->search) - 1);
 	key->search[sizeof(key->search) - 1] = '\0';
 }
 
 int ndb_search_profile(struct ndb_txn *txn, struct ndb_search *search, const char *query)
 {
 	int rc;
 	struct ndb_search_key s;
 	MDB_val k, v;
 	search->cursor = NULL;
 
 	MDB_cursor **cursor = (MDB_cursor **)&search->cursor;
 
 	ndb_make_search_key_low(&s, query);
 
 	k.mv_data = &s;
 	k.mv_size = sizeof(s);
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn,
 				  txn->lmdb->dbs[NDB_DB_PROFILE_SEARCH],
 				  cursor))) {
 		printf("search_profile: cursor opened failed: %s\n",
 				mdb_strerror(rc));
 		return 0;
 	}
 
 	// Position cursor at the next key greater than or equal to the specified key
 	if (mdb_cursor_get(search->cursor, &k, &v, MDB_SET_RANGE)) {
 		printf("search_profile: cursor get failed\n");
 		goto cleanup;
 	} else {
 		search->key = k.mv_data;
 		assert(v.mv_size == 8);
 		search->profile_key = *((uint64_t*)v.mv_data);
 		return 1;
 	}
 
 cleanup:
 	mdb_cursor_close(search->cursor);
 	search->cursor = NULL;
 	return 0;
 }
 
 void ndb_search_profile_end(struct ndb_search *search)
 {
 	if (search->cursor)
 		mdb_cursor_close(search->cursor);
 }
 
 int ndb_search_profile_next(struct ndb_search *search)
 {
 	int rc;
 	MDB_val k, v;
 	unsigned char *init_id;
 
 	init_id = search->key->id;
 	k.mv_data = search->key;
 	k.mv_size = sizeof(*search->key);
 
 retry:
 	if ((rc = mdb_cursor_get(search->cursor, &k, &v, MDB_NEXT))) {
 		ndb_debug("ndb_search_profile_next: %s\n",
 				mdb_strerror(rc));
 		return 0;
 	} else {
 		search->key = k.mv_data;
 		assert(v.mv_size == 8);
 		search->profile_key = *((uint64_t*)v.mv_data);
 
 		// skip duplicate pubkeys
 		if (!memcmp(init_id, search->key->id, 32))
 			goto retry;
 	}
 
 	return 1;
 }
 
 //
 // The relay kind index has a layout like so (so we don't need dupsort)
 //
 // - note_id:        00 + 8 bytes
 // - kind:           08 + 8 bytes
 // - created_at:     16 + 8 bytes
 // - relay_url_size: 24 + 1 byte
 // - relay_url:      25 + n byte null-terminated string
 // - pad to 8 byte alignment
 //
 // The key sort order is:
 //
 // relay_url, kind, created_at
 //
 static int ndb_relay_kind_cmp(const MDB_val *a, const MDB_val *b)
 {
 	int cmp;
 	MDB_val va, vb;
 	uint64_t iva, ivb;
 	unsigned char *ad = (unsigned char *)a->mv_data;
 	unsigned char *bd = (unsigned char *)b->mv_data;
 	assert(((uint64_t)a->mv_data % 8) == 0);
 
 	va.mv_size = *(ad + 24);
 	va.mv_data =   ad + 25;
 
 	vb.mv_size = *(bd + 24);
 	vb.mv_data =   bd + 25;
 
 	cmp = mdb_cmp_memn(&va, &vb);
 	if (cmp) return cmp;
 
 	// kind
 	iva = *(uint64_t*)(ad + 8);
 	ivb = *(uint64_t*)(bd + 8);
 
 	if (iva < ivb)
 		return -1;
 	else if (iva > ivb)
 		return 1;
 
 	// created_at
 	iva = *(uint64_t*)(ad + 16);
 	ivb = *(uint64_t*)(bd + 16);
 
 	if (iva < ivb)
 		return -1;
 	else if (iva > ivb)
 		return 1;
 
 	// note_id (so we don't need dupsort logic)
 	iva = *(uint64_t*)ad;
 	ivb = *(uint64_t*)bd;
 
 	if (iva < ivb)
 		return -1;
 	else if (iva > ivb)
 		return 1;
 
 	return 0;
 }
 
 static int ndb_search_key_cmp(const MDB_val *a, const MDB_val *b)
 {
 	int cmp;
 	struct ndb_search_key *ska, *skb;
 
 	ska = a->mv_data;
 	skb = b->mv_data;
 
 	MDB_val a2 = *a;
 	MDB_val b2 = *b;
 
 	a2.mv_data = ska->search;
 	a2.mv_size = sizeof(ska->search) + sizeof(ska->id);
 
 	cmp = mdb_cmp_memn(&a2, &b2);
 	if (cmp) return cmp;
 
 	if (ska->timestamp < skb->timestamp)
 		return -1;
 	else if (ska->timestamp > skb->timestamp)
 		return 1;
 
 	return 0;
 }
 
 static int ndb_write_profile_pk_index(struct ndb_txn *txn, struct ndb_note *note, uint64_t profile_key)
 
 {
 	MDB_val key, val;
 	int rc;
 	struct ndb_tsid tsid;
 	MDB_dbi pk_db;
 
 	pk_db = txn->lmdb->dbs[NDB_DB_PROFILE_PK];
 
 	// write profile_pk + created_at index
 	ndb_tsid_init(&tsid, note->pubkey, note->created_at);
 
 	key.mv_data = &tsid;
 	key.mv_size = sizeof(tsid);
 	val.mv_data = &profile_key;
 	val.mv_size = sizeof(profile_key);
 
 	if ((rc = mdb_put(txn->mdb_txn, pk_db, &key, &val, 0))) {
 		ndb_debug("write profile_pk(%" PRIu64 ") to db failed: %s\n",
 				profile_key, mdb_strerror(rc));
 		return 0;
 	}
 
 	return 1;
 }
 
 static int ndb_write_profile(struct ndb_txn *txn,
 			     struct ndb_writer_profile *profile,
 			     uint64_t note_key)
 {
 	uint64_t profile_key;
 	struct ndb_note *note;
 	void *flatbuf;
 	size_t flatbuf_len;
 	int rc;
 
 	MDB_val key, val;
 	MDB_dbi profile_db;
 
 	note = profile->note.note;
 
 	// add note_key to profile record
 	NdbProfileRecord_note_key_add(profile->record.builder, note_key);
 	NdbProfileRecord_end_as_root(profile->record.builder);
 
 	flatbuf = profile->record.flatbuf =
 		flatcc_builder_finalize_aligned_buffer(profile->record.builder, &flatbuf_len);
 
 	assert(((uint64_t)flatbuf % 8) == 0);
 
 	// TODO: this may not be safe!?
 	flatbuf_len = (flatbuf_len + 7) & ~7;
 
 	//assert(NdbProfileRecord_verify_as_root(flatbuf, flatbuf_len) == 0);
 
 	// get dbs
 	profile_db = txn->lmdb->dbs[NDB_DB_PROFILE];
 
 	// get new key
 	profile_key = ndb_get_last_key(txn->mdb_txn, profile_db) + 1;
 
 	// write profile to profile store
 	key.mv_data = &profile_key;
 	key.mv_size = sizeof(profile_key);
 	val.mv_data = flatbuf;
 	val.mv_size = flatbuf_len;
 
 	if ((rc = mdb_put(txn->mdb_txn, profile_db, &key, &val, 0))) {
 		ndb_debug("write profile to db failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 
 	// write last fetched record
 	if (!ndb_maybe_write_last_profile_fetch(txn, note)) {
 		ndb_debug("failed to write last profile fetched record\n");
 	}
 
 	// write profile pubkey index
 	if (!ndb_write_profile_pk_index(txn, note, profile_key)) {
 		ndb_debug("failed to write profile pubkey index\n");
 		return 0;
 	}
 
 	// write name, display_name profile search indices
 	if (!ndb_write_profile_search_indices(txn, note, profile_key,
 					      flatbuf)) {
 		ndb_debug("failed to write profile search indices\n");
 		return 0;
 	}
 
 	return 1;
 }
 
 // find the last id tag in a note (e, p, etc)
 static unsigned char *ndb_note_last_id_tag(struct ndb_note *note, char type)
 {
 	unsigned char *last = NULL;
 	struct ndb_iterator iter;
 	struct ndb_str str;
 
 	// get the liked event id (last id)
 	ndb_tags_iterate_start(note, &iter);
 
 	while (ndb_tags_iterate_next(&iter)) {
 		if (iter.tag->count < 2)
 			continue;
 
 		str = ndb_tag_str(note, iter.tag, 0);
 
 		// assign liked to the last e tag
 		if (str.flag == NDB_PACKED_STR && str.str[0] == type) {
 			str = ndb_tag_str(note, iter.tag, 1);
 			if (str.flag == NDB_PACKED_ID)
 				last = str.id;
 		}
 	}
 
 	return last;
 }
 
 void *ndb_get_note_meta(struct ndb_txn *txn, const unsigned char *id, size_t *len)
 {
 	MDB_val k, v;
 
 	k.mv_data = (unsigned char*)id;
 	k.mv_size = 32;
 
 	if (mdb_get(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_META], &k, &v)) {
 		//ndb_debug("ndb_get_note_meta: mdb_get note failed\n");
 		return NULL;
 	}
 
 	if (len)
 		*len = v.mv_size;
 
 	return v.mv_data;
 }
 
 // When receiving a reaction note, look for the liked id and increase the
 // reaction counter in the note metadata database
 static int ndb_write_reaction_stats(struct ndb_txn *txn, struct ndb_note *note)
 {
 	size_t len;
 	void *root;
 	int reactions, rc;
 	MDB_val key, val;
 	NdbEventMeta_table_t meta;
 	unsigned char *liked = ndb_note_last_id_tag(note, 'e');
 
 	if (liked == NULL)
 		return 0;
 
 	root = ndb_get_note_meta(txn, liked, &len);
 
 	flatcc_builder_t builder;
 	flatcc_builder_init(&builder);
 	NdbEventMeta_start_as_root(&builder);
 
 	// no meta record, let's make one
 	if (root == NULL) {
 		NdbEventMeta_reactions_add(&builder, 1);
 	} else {
 		// clone existing and add to it
 		meta = NdbEventMeta_as_root(root);
 
 		reactions = NdbEventMeta_reactions_get(meta);
 		NdbEventMeta_clone(&builder, meta);
 		NdbEventMeta_reactions_add(&builder, reactions + 1);
 	}
 
 	NdbProfileRecord_end_as_root(&builder);
 	root = flatcc_builder_finalize_aligned_buffer(&builder, &len);
 	assert(((uint64_t)root % 8) == 0);
 
 	if (root == NULL) {
 		ndb_debug("failed to create note metadata record\n");
 		return 0;
 	}
 
 	// metadata is keyed on id because we want to collect stats regardless
 	// if we have the note yet or not
 	key.mv_data = liked;
 	key.mv_size = 32;
 
 	val.mv_data = root;
 	val.mv_size = len;
 
 	// write the new meta record
 	//ndb_debug("writing stats record for ");
 	//print_hex(liked, 32);
 	//ndb_debug("\n");
 
 	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_META], &key, &val, 0))) {
 		ndb_debug("write reaction stats to db failed: %s\n", mdb_strerror(rc));
 		free(root);
 		return 0;
 	}
 
 	free(root);
 
 	return 1;
 }
 
 
 static int ndb_write_note_id_index(struct ndb_txn *txn, struct ndb_note *note,
 				   uint64_t note_key)
 
 {
 	struct ndb_tsid tsid;
 	int rc;
 	MDB_val key, val;
 	MDB_dbi id_db;
 
 	ndb_tsid_init(&tsid, note->id, note->created_at);
 
 	key.mv_data = &tsid;
 	key.mv_size = sizeof(tsid);
 	val.mv_data = &note_key;
 	val.mv_size = sizeof(note_key);
 
 	id_db = txn->lmdb->dbs[NDB_DB_NOTE_ID];
 
 	if ((rc = mdb_put(txn->mdb_txn, id_db, &key, &val, 0))) {
 		ndb_debug("write note id index to db failed: %s\n",
 				mdb_strerror(rc));
 		return 0;
 	}
 
 	return 1;
 }
 
 static int ndb_filter_group_add_filters(struct ndb_filter_group *group,
 					struct ndb_filter *filters,
 					int num_filters)
 {
 	int i;
 
 	for (i = 0; i < num_filters; i++) {
 		if (!ndb_filter_group_add(group, &filters[i]))
 			return 0;
 	}
 
 	return 1;
 }
 
 
 static struct ndb_filter_elements *
 ndb_filter_find_elements(struct ndb_filter *filter, enum ndb_filter_fieldtype typ)
 {
 	int i;
 	struct ndb_filter_elements *els;
 
 	for (i = 0; i < filter->num_elements; i++) {
 		els = ndb_filter_get_elements(filter, i);
 		assert(els);
 		if (els->field.type == typ) {
 			return els;
 		}
 	}
 
 	return NULL;
 }
 
 static const char *ndb_filter_find_search(struct ndb_filter *filter)
 {
 	struct ndb_filter_elements *els;
 
 	if (!(els = ndb_filter_find_elements(filter, NDB_FILTER_SEARCH)))
 		return NULL;
 
 	return ndb_filter_get_string_element(filter, els, 0);
 }
 
 int ndb_filter_is_subset_of(const struct ndb_filter *a, const struct ndb_filter *b)
 {
 	int i;
 	struct ndb_filter_elements *b_field, *a_field;
 
         // Everything is always a subset of {}
 	if (b->num_elements == 0)
 		return 1;
 
         // We can't be a subset if the number of elements in the other
         // filter is larger then the number of elements we have.
 	if (b->num_elements > a->num_elements)
 		return 0;
 
         // If our filter count matches, we can only be a subset if we are
         // equal
 	if (b->num_elements == a->num_elements)
 		return ndb_filter_eq(a, b);
 
         // If our element count is larger than the other filter, then we
         // must see if every element in the other filter exists in ours. If
         // so, then we are a subset of the other.
         //
         // eg: B={k:1, a:b} <- A={t:x, k:1, a:b}
         //
         // A is a subset of B because `k:1` and `a:b` both exist in A
 
 	for (i = 0; i < b->num_elements; i++) {
 		b_field = ndb_filter_get_elements((struct ndb_filter*)b, i);
 		a_field = ndb_filter_find_elements((struct ndb_filter*)a,
 						   b_field->field.type);
 
 		if (a_field == NULL)
 			return 0;
 
 		if (!ndb_filter_field_eq((struct ndb_filter*)a, a_field,
 					 (struct ndb_filter*)b, b_field))
 			return 0;
 	}
 
 	return 1;
 }
 
 int ndb_filter_eq(const struct ndb_filter *a, const struct ndb_filter *b)
 {
 	int i;
 	struct ndb_filter_elements *a_els, *b_els;
 
 	if (a->num_elements != b->num_elements)
 		return 0;
 
 	for (i = 0; i < a->num_elements; i++) {
 		a_els = ndb_filter_get_elements((struct ndb_filter*)a, i);
 		b_els = ndb_filter_find_elements((struct ndb_filter *)b,
 						 a_els->field.type);
 
 		if (b_els == NULL)
 			return 0;
 
 		if (!ndb_filter_field_eq((struct ndb_filter*)a, a_els,
 					 (struct ndb_filter*)b, b_els))
 			return 0;
 	}
 
 	return 1;
 }
 
 
 static uint64_t *
 ndb_filter_get_elem(struct ndb_filter *filter, enum ndb_filter_fieldtype typ)
 {
 	struct ndb_filter_elements *els;
 	if ((els = ndb_filter_find_elements(filter, typ)))
 		return &els->elements[0];
 	return NULL;
 }
 
 static uint64_t *ndb_filter_get_int(struct ndb_filter *filter,
 				    enum ndb_filter_fieldtype typ)
 {
 	uint64_t *el;
 	if (NULL == (el = ndb_filter_get_elem(filter, typ)))
 		return NULL;
 	return el;
 }
 
 static inline int push_query_result(struct ndb_query_results *results,
 				    struct ndb_query_result *result)
 {
 	return cursor_push(&results->cur, (unsigned char*)result, sizeof(*result));
 }
 
 static int compare_query_results(const void *pa, const void *pb)
 {
 	struct ndb_query_result *a, *b;
 
 	a = (struct ndb_query_result *)pa;
 	b = (struct ndb_query_result *)pb;
 
 	if (a->note->created_at == b->note->created_at) {
 		return 0;
 	} else if (a->note->created_at > b->note->created_at) {
 		return -1;
 	} else {
 		return 1;
 	}
 }
 
 static void ndb_query_result_init(struct ndb_query_result *res,
 				  struct ndb_note *note,
 				  uint64_t note_size,
 				  uint64_t note_id)
 {
 	*res = (struct ndb_query_result){
 		.note_id = note_id,
 		.note_size = note_size,
 		.note = note,
 	};
 }
 
 static int query_is_full(struct ndb_query_results *results, int limit)
 {
 	if (results->cur.p >= results->cur.end)
 		return 1;
 
 	return cursor_count(&results->cur, sizeof(struct ndb_query_result)) >= limit;
 }
 
 static int ndb_query_plan_execute_search(struct ndb_txn *txn,
 					 struct ndb_filter *filter,
 					 struct ndb_query_results *results,
 					 int limit)
 {
 	const char *search;
 	int i;
 	struct ndb_text_search_results text_results;
 	struct ndb_text_search_result *text_result;
 	struct ndb_text_search_config config;
 	struct ndb_query_result result;
 
 	ndb_default_text_search_config(&config);
 
 	if (!(search = ndb_filter_find_search(filter)))
 		return 0;
 
 	if (!ndb_text_search_with(txn, search, &text_results, &config, filter))
 		return 0;
 
 	for (i = 0; i < text_results.num_results; i++) {
 		if (query_is_full(results, limit))
 			break;
 
 		text_result = &text_results.results[i];
 
 		result.note = text_result->note;
 		result.note_size = text_result->note_size;
 		result.note_id = text_result->key.note_id;
 
 		if (!push_query_result(results, &result))
 			break;
 	}
 
 	return 1;
 }
 
 static int ndb_query_plan_execute_ids(struct ndb_txn *txn,
 				      struct ndb_filter *filter,
 				      struct ndb_query_results *results,
 				      int limit)
 {
 	MDB_cursor *cur;
 	MDB_dbi db;
 	MDB_val k, v;
 	int rc, i;
 	struct ndb_filter_elements *ids;
 	struct ndb_note *note;
 	struct ndb_query_result res;
 	struct ndb_tsid tsid, *ptsid;
 	uint64_t note_id, until, *pint;
 	size_t note_size;
 	unsigned char *id;
 
 	until = UINT64_MAX;
 
 	if (!(ids = ndb_filter_find_elements(filter, NDB_FILTER_IDS)))
 		return 0;
 
 	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
 		until = *pint;
 
 	db = txn->lmdb->dbs[NDB_DB_NOTE_ID];
 	if ((rc = mdb_cursor_open(txn->mdb_txn, db, &cur)))
 		return 0;
 
 	// for each id in our ids filter, find in the db
 	for (i = 0; i < ids->count; i++) {
 		if (query_is_full(results, limit))
 			break;
 
 		id = ndb_filter_get_id_element(filter, ids, i);
 		ndb_tsid_init(&tsid, (unsigned char *)id, until);
 
 		k.mv_data = &tsid;
 		k.mv_size = sizeof(tsid);
 
 		if (!ndb_cursor_start(cur, &k, &v))
 			continue;
 
 		ptsid = (struct ndb_tsid *)k.mv_data;
 		note_id = *(uint64_t*)v.mv_data;
 
 		if (memcmp(id, ptsid->id, 32))
 			continue;
 
 		// get the note because we need it to match against the filter
 		if (!(note = ndb_get_note_by_key(txn, note_id, &note_size)))
 			continue;
 
 		// Sure this particular lookup matched the index query, but
 		// does it match the entire filter? Check! We also pass in
 		// things we've already matched via the filter so we don't have
 		// to check again. This can be pretty important for filters
 		// with a large number of entries.
 		if (!ndb_filter_matches_with(filter, note, 1 << NDB_FILTER_IDS))
 			continue;
 
 		ndb_query_result_init(&res, note, note_size, note_id);
 		if (!push_query_result(results, &res))
 			break;
 	}
 
 	mdb_cursor_close(cur);
 	return 1;
 }
 
 //
 // encode a tag index key
 //
 // consists of:
 //
 //   u8   tag
 //   u8   tag_val_len
 //   [u8] tag_val_bytes
 //   u64  created_at
 //
 static int ndb_encode_tag_key(unsigned char *buf, int buf_size,
 			      char tag, const unsigned char *val,
 			      unsigned char val_len,
 			      uint64_t timestamp)
 {
 	struct cursor writer;
 	int ok;
 
 	// quick exit for obvious case where it will be too big. There can be
 	// values of val_len that still fail, but we just let the writer handle
 	// those failure cases
 	if (val_len >= buf_size)
 		return 0;
 
 	make_cursor(buf, buf + buf_size, &writer);
 
 	ok =
 		cursor_push_byte(&writer, tag) &&
 		cursor_push(&writer, (unsigned char*)val, val_len) &&
 		cursor_push(&writer, (unsigned char*)&timestamp, sizeof(timestamp));
 
 	if (!ok)
 		return 0;
 
 	return writer.p - writer.start;
 }
 
 static int ndb_query_plan_execute_authors(struct ndb_txn *txn,
 					  struct ndb_filter *filter,
 					  struct ndb_query_results *results,
 					  int limit)
 {
 	MDB_val k, v;
 	MDB_cursor *cur;
 	int rc, i;
 	uint64_t *pint, until, since, note_key;
 	unsigned char *author;
 	struct ndb_note *note;
 	size_t note_size;
 	struct ndb_filter_elements *authors;
 	struct ndb_query_result res;
 	struct ndb_tsid tsid, *ptsid;
 	enum ndb_dbs db;
 
 	db = txn->lmdb->dbs[NDB_DB_NOTE_PUBKEY];
 
 	if (!(authors = ndb_filter_find_elements(filter, NDB_FILTER_AUTHORS)))
 		return 0;
 
 	until = UINT64_MAX;
 	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
 		until = *pint;
 
 	since = 0;
 	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_SINCE)))
 		since = *pint;
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn, db, &cur)))
 		return 0;
 
 	for (i = 0; i < authors->count; i++) {
 		author = ndb_filter_get_id_element(filter, authors, i);
 
 		ndb_tsid_init(&tsid, author, until);
 
 		k.mv_data = &tsid;
 		k.mv_size = sizeof(tsid);
 
 		if (!ndb_cursor_start(cur, &k, &v))
 			continue;
 
 		// for each id in our ids filter, find in the db
 		while (!query_is_full(results, limit)) {
 			ptsid = (struct ndb_tsid *)k.mv_data;
 			note_key = *(uint64_t*)v.mv_data;
 
 			// don't continue the scan if we're below `since`
 			if (ptsid->timestamp < since)
 				break;
 
 			// our author should match, if not bail
 			if (memcmp(author, ptsid->id, 32))
 				break;
 
 			// fetch the note, we need it for our query results
 			// and to match further against the filter
 			if (!(note = ndb_get_note_by_key(txn, note_key, &note_size)))
 				goto next;
 
 			if (!ndb_filter_matches_with(filter, note, 1 << NDB_FILTER_AUTHORS))
 				goto next;
 
 			ndb_query_result_init(&res, note, note_size, note_key);
 			if (!push_query_result(results, &res))
 				break;
 
 next:
 			if (mdb_cursor_get(cur, &k, &v, MDB_PREV))
 				break;
 		}
 	}
 
 	mdb_cursor_close(cur);
 	return 1;
 }
 
 static int ndb_query_plan_execute_created_at(struct ndb_txn *txn,
 					     struct ndb_filter *filter,
 					     struct ndb_query_results *results,
 					     int limit)
 {
 	MDB_dbi db;
 	MDB_val k, v;
 	MDB_cursor *cur;
 	int rc;
 	struct ndb_note *note;
 	struct ndb_tsid key, *pkey;
 	uint64_t *pint, until, since, note_id;
 	size_t note_size;
 	struct ndb_query_result res;
 	unsigned char high_key[32] = {0xFF};
 
 	db = txn->lmdb->dbs[NDB_DB_NOTE_ID];
 
 	until = UINT64_MAX;
 	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
 		until = *pint;
 
 	since = 0;
 	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_SINCE)))
 		since = *pint;
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn, db, &cur)))
 		return 0;
 
 	// if we have until, start there, otherwise just use max
 	ndb_tsid_init(&key, high_key, until);
 	k.mv_data = &key;
 	k.mv_size = sizeof(key);
 
 	if (!ndb_cursor_start(cur, &k, &v))
 		return 1;
 
 	while (!query_is_full(results, limit)) {
 		pkey = (struct ndb_tsid *)k.mv_data;
 		note_id = *(uint64_t*)v.mv_data;
 		assert(v.mv_size == 8);
 
 		// don't continue the scan if we're below `since`
 		if (pkey->timestamp < since)
 			break;
 
 		if (!(note = ndb_get_note_by_key(txn, note_id, &note_size)))
 			goto next;
 
 		// does this entry match our filter?
 		if (!ndb_filter_matches_with(filter, note, 0))
 			goto next;
 
 		ndb_query_result_init(&res, note, (uint64_t)note_size, note_id);
 		if (!push_query_result(results, &res))
 			break;
 next:
 		if (mdb_cursor_get(cur, &k, &v, MDB_PREV))
 			break;
 	}
 
 	mdb_cursor_close(cur);
 	return 1;
 }
 
 static int ndb_query_plan_execute_tags(struct ndb_txn *txn,
 				       struct ndb_filter *filter,
 				       struct ndb_query_results *results,
 				       int limit)
 {
 	MDB_cursor *cur;
 	MDB_dbi db;
 	MDB_val k, v;
 	int len, taglen, rc, i;
 	uint64_t *pint, until, note_id;
 	size_t note_size;
 	unsigned char key_buffer[255];
 	struct ndb_note *note;
 	struct ndb_filter_elements *tags;
 	unsigned char *tag;
 	struct ndb_query_result res;
 
 	db = txn->lmdb->dbs[NDB_DB_NOTE_TAGS];
 
 	if (!(tags = ndb_filter_find_elements(filter, NDB_FILTER_TAGS)))
 		return 0;
 
 	until = UINT64_MAX;
 	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
 		until = *pint;
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn, db, &cur)))
 		return 0;
 
 	for (i = 0; i < tags->count; i++) {
 		tag = ndb_filter_get_id_element(filter, tags, i);
 
 		taglen = tags->field.elem_type == NDB_ELEMENT_ID
 		       ? 32 : strlen((const char*)tag);
 
 		if (!(len = ndb_encode_tag_key(key_buffer, sizeof(key_buffer),
 					       tags->field.tag, tag, taglen,
 					       until)))
 			return 0;
 
 		k.mv_data = key_buffer;
 		k.mv_size = len;
 
 		if (!ndb_cursor_start(cur, &k, &v))
 			continue;
 
 		// for each id in our ids filter, find in the db
 		while (!query_is_full(results, limit)) {
 			// check if tag value matches, bail if not
 			if (((unsigned char *)k.mv_data)[0] != tags->field.tag)
 				break;
 
 			// check if tag value matches, bail if not
 			if (taglen != k.mv_size - 9)
 				break;
 
 			if (memcmp((unsigned char *)k.mv_data+1, tag, k.mv_size-9))
 				break;
 
 			note_id = *(uint64_t*)v.mv_data;
 
 			if (!(note = ndb_get_note_by_key(txn, note_id, &note_size)))
 				goto next;
 
 			if (!ndb_filter_matches_with(filter, note, 1 << NDB_FILTER_TAGS))
 				goto next;
 
 			ndb_query_result_init(&res, note, note_size, note_id);
 			if (!push_query_result(results, &res))
 				break;
 
 next:
 			if (mdb_cursor_get(cur, &k, &v, MDB_PREV))
 				break;
 		}
 	}
 
 	mdb_cursor_close(cur);
 	return 1;
 }
 
 static int ndb_query_plan_execute_kinds(struct ndb_txn *txn,
 					struct ndb_filter *filter,
 					struct ndb_query_results *results,
 					int limit)
 {
 	MDB_cursor *cur;
 	MDB_dbi db;
 	MDB_val k, v;
 	struct ndb_note *note;
 	struct ndb_u64_ts tsid, *ptsid;
 	struct ndb_filter_elements *kinds;
 	struct ndb_query_result res;
 	uint64_t kind, note_id, until, since, *pint;
 	size_t note_size;
 	int i, rc;
 
 	// we should have kinds in a kinds filter!
 	if (!(kinds = ndb_filter_find_elements(filter, NDB_FILTER_KINDS)))
 		return 0;
 
 	until = UINT64_MAX;
 	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
 		until = *pint;
 
 	since = 0;
 	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_SINCE)))
 		since = *pint;
 
 	db = txn->lmdb->dbs[NDB_DB_NOTE_KIND];
 
 	if ((rc = mdb_cursor_open(txn->mdb_txn, db, &cur)))
 		return 0;
 
 	for (i = 0; i < kinds->count; i++) {
 		if (query_is_full(results, limit))
 			break;
 
 		kind = kinds->elements[i];
 		ndb_debug("kind %" PRIu64 "\n", kind);
 		ndb_u64_ts_init(&tsid, kind, until);
 
 		k.mv_data = &tsid;
 		k.mv_size = sizeof(tsid);
 
 		if (!ndb_cursor_start(cur, &k, &v))
 			continue;
 
 		// for each id in our ids filter, find in the db
 		while (!query_is_full(results, limit)) {
 			ptsid = (struct ndb_u64_ts *)k.mv_data;
 			if (ptsid->u64 != kind)
 				break;
 
 			// don't continue the scan if we're below `since`
 			if (ptsid->timestamp < since)
 				break;
 
 			note_id = *(uint64_t*)v.mv_data;
 			if (!(note = ndb_get_note_by_key(txn, note_id, &note_size)))
 				goto next;
 
 			if (!ndb_filter_matches_with(filter, note, 1 << NDB_FILTER_KINDS))
 				goto next;
 
 			ndb_query_result_init(&res, note, note_size, note_id);
 			if (!push_query_result(results, &res))
 				break;
 
 next:
 			if (mdb_cursor_get(cur, &k, &v, MDB_PREV))
 				break;
 		}
 	}
 
 	mdb_cursor_close(cur);
 	return 1;
 }
 
 static enum ndb_query_plan ndb_filter_plan(struct ndb_filter *filter)
 {
 	struct ndb_filter_elements *ids, *kinds, *authors, *tags, *search;
 
 	ids = ndb_filter_find_elements(filter, NDB_FILTER_IDS);
 	search = ndb_filter_find_elements(filter, NDB_FILTER_SEARCH);
 	kinds = ndb_filter_find_elements(filter, NDB_FILTER_KINDS);
 	authors = ndb_filter_find_elements(filter, NDB_FILTER_AUTHORS);
 	tags = ndb_filter_find_elements(filter, NDB_FILTER_TAGS);
 
 	// this is rougly similar to the heuristic in strfry's dbscan
 	if (search) {
 		return NDB_PLAN_SEARCH;
 	} else if (ids) {
 		return NDB_PLAN_IDS;
 	} else if (kinds && authors && authors->count <= 10) {
 		return NDB_PLAN_AUTHOR_KINDS;
 	} else if (authors && authors->count <= 10) {
 		return NDB_PLAN_AUTHORS;
 	} else if (tags && tags->count <= 10) {
 		return NDB_PLAN_TAGS;
 	} else if (kinds) {
 		return NDB_PLAN_KINDS;
 	}
 
 	return NDB_PLAN_CREATED;
 }
 
 static const char *ndb_query_plan_name(int plan_id)
 {
 	switch (plan_id) {
 		case NDB_PLAN_IDS:     return "ids";
 		case NDB_PLAN_SEARCH:  return "search";
 		case NDB_PLAN_KINDS:   return "kinds";
 		case NDB_PLAN_TAGS:    return "tags";
 		case NDB_PLAN_CREATED: return "created";
 		case NDB_PLAN_AUTHORS: return "authors";
 	}
 
 	return "unknown";
 }
 
 static int ndb_query_filter(struct ndb_txn *txn, struct ndb_filter *filter,
 			    struct ndb_query_result *res, int capacity,
 			    int *results_out)
 {
 	struct ndb_query_results results;
 	uint64_t limit, *pint;
 	enum ndb_query_plan plan;
 	limit = capacity;
 
 	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_LIMIT)))
 		limit = *pint;
 
 	limit = min(capacity, limit);
 	make_cursor((unsigned char *)res,
 		    ((unsigned char *)res) + limit * sizeof(*res),
 		    &results.cur);
 
 	plan = ndb_filter_plan(filter);
 	ndb_debug("using query plan '%s'\n", ndb_query_plan_name(plan));
 	switch (plan) {
 	// We have a list of ids, just open a cursor and jump to each once
 	case NDB_PLAN_IDS:
 		if (!ndb_query_plan_execute_ids(txn, filter, &results, limit))
 			return 0;
 		break;
 
 	case NDB_PLAN_SEARCH:
 		if (!ndb_query_plan_execute_search(txn, filter, &results, limit))
 			return 0;
 		break;
 
 	// We have just kinds, just scan the kind index
 	case NDB_PLAN_KINDS:
 		if (!ndb_query_plan_execute_kinds(txn, filter, &results, limit))
 			return 0;
 		break;
 
 	case NDB_PLAN_TAGS:
 		if (!ndb_query_plan_execute_tags(txn, filter, &results, limit))
 			return 0;
 		break;
 	case NDB_PLAN_CREATED:
 		if (!ndb_query_plan_execute_created_at(txn, filter, &results, limit))
 			return 0;
 		break;
 	case NDB_PLAN_AUTHORS:
 		if (!ndb_query_plan_execute_authors(txn, filter, &results, limit))
 			return 0;
 		break;
 	case NDB_PLAN_AUTHOR_KINDS:
 		/* TODO: author kinds
 		if (!ndb_query_plan_execute_author_kinds(txn, filter, &results, limit))
 			return 0;
 			*/
 		if (!ndb_query_plan_execute_authors(txn, filter, &results, limit))
 			return 0;
 		break;
 	}
 
 	*results_out = cursor_count(&results.cur, sizeof(*res));
 	return 1;
 }
 
 int ndb_query(struct ndb_txn *txn, struct ndb_filter *filters, int num_filters,
 	      struct ndb_query_result *results, int result_capacity, int *count)
 {
 	int i, out;
 	struct ndb_query_result *p = results;
 
 	out = 0;
 	*count = 0;
 
 	for (i = 0; i < num_filters; i++) {
 		if (!ndb_query_filter(txn, &filters[i], p,
 				      result_capacity, &out)) {
 			return 0;
 		}
 
 		*count += out;
 		p += out;
 		result_capacity -= out;
 		if (result_capacity <= 0)
 			break;
 	}
 
 	// sort results
 	qsort(results, *count, sizeof(*results), compare_query_results);
 	return 1;
 }
 
 static int ndb_write_note_tag_index(struct ndb_txn *txn, struct ndb_note *note,
 				    uint64_t note_key)
 {
 	unsigned char key_buffer[255];
 	struct ndb_iterator iter;
 	struct ndb_str tkey, tval;
 	char tchar;
 	int len, rc;
 	MDB_val key, val;
 	MDB_dbi tags_db;
 
 	tags_db = txn->lmdb->dbs[NDB_DB_NOTE_TAGS];
 
 	ndb_tags_iterate_start(note, &iter);
 
 	while (ndb_tags_iterate_next(&iter)) {
 		if (iter.tag->count < 2)
 			continue;
 
 		tkey = ndb_tag_str(note, iter.tag, 0);
 
 		// we only write indices for 1-char tags.
 		tchar = tkey.str[0];
 		if (tchar == 0 || tkey.str[1] != 0)
 			continue;
 
 		tval = ndb_tag_str(note, iter.tag, 1);
 		len = ndb_str_len(&tval);
 
 		if (!(len = ndb_encode_tag_key(key_buffer, sizeof(key_buffer),
 					       tchar, tval.id, (unsigned char)len,
 					       ndb_note_created_at(note)))) {
 			// this will fail when we try to encode a key that is
 			// too big
 			continue;
 		}
 
 		//ndb_debug("writing tag '%c':'data:%d' to index\n", tchar, len);
 
 		key.mv_data = key_buffer;
 		key.mv_size = len;
 
 		val.mv_data = &note_key;
 		val.mv_size = sizeof(note_key);
 
 		if ((rc = mdb_put(txn->mdb_txn, tags_db, &key, &val, 0))) {
 			ndb_debug("write note tag index to db failed: %s\n",
 					mdb_strerror(rc));
 			return 0;
 		}
 	}
 
 	return 1;
 }
 
 static int ndb_write_note_kind_index(struct ndb_txn *txn, struct ndb_note *note,
 				     uint64_t note_key)
 {
 	struct ndb_u64_ts tsid;
 	int rc;
 	MDB_val key, val;
 	MDB_dbi kind_db;
 
 	ndb_u64_ts_init(&tsid, note->kind, note->created_at);
 
 	key.mv_data = &tsid;
 	key.mv_size = sizeof(tsid);
 	val.mv_data = &note_key;
 	val.mv_size = sizeof(note_key);
 
 	kind_db = txn->lmdb->dbs[NDB_DB_NOTE_KIND];
 
 	if ((rc = mdb_put(txn->mdb_txn, kind_db, &key, &val, 0))) {
 		ndb_debug("write note kind index to db failed: %s\n",
 				mdb_strerror(rc));
 		return 0;
 	}
 
 	return 1;
 }
 
 static int ndb_write_word_to_index(struct ndb_txn *txn, const char *word,
 				   int word_len, int word_index,
 				   uint64_t timestamp, uint64_t note_id)
 {
 	// cap to some reasonable key size
 	unsigned char buffer[1024];
 	int keysize, rc;
 	MDB_val k, v;
 	MDB_dbi text_db;
 
 	// build our compressed text index key
 	if (!ndb_make_text_search_key(buffer, sizeof(buffer), word_index,
 				      word_len, word, timestamp, note_id,
 				      &keysize)) {
 		// probably too big
 
 		return 0;
 	}
 
 	k.mv_data = buffer;
 	k.mv_size = keysize;
 
 	v.mv_data = NULL;
 	v.mv_size = 0;
 
 	text_db = txn->lmdb->dbs[NDB_DB_NOTE_TEXT];
 
 	if ((rc = mdb_put(txn->mdb_txn, text_db, &k, &v, 0))) {
 		ndb_debug("write note text index to db failed: %s\n",
 				mdb_strerror(rc));
 		return 0;
 	}
 
 	return 1;
 }
 
 
 
 // break a string into individual words for querying or for building the
 // fulltext search index. This is callback based so we don't need to
 // build up an intermediate structure
 static int ndb_parse_words(struct cursor *cur, void *ctx, ndb_word_parser_fn fn)
 {
 	int word_len, words;
 	const char *word;
 
 	words = 0;
 
 	while (cur->p < cur->end) {
 		consume_whitespace_or_punctuation(cur);
 		if (cur->p >= cur->end)
 			break;
 		word = (const char *)cur->p;
 
 		if (!consume_until_boundary(cur))
 			break;
 
 		// start of word or end
 		word_len = cur->p - (unsigned char *)word;
 		if (word_len == 0 && cur->p >= cur->end)
 			break;
 
 		if (word_len == 0) {
 			if (!cursor_skip(cur, 1))
 				break;
 			continue;
 		}
 
 		//ndb_debug("writing word index '%.*s'\n", word_len, word);
 
 		if (!fn(ctx, word, word_len, words))
 			continue;
 
 		words++;
 	}
 
 	return 1;
 }
 
 struct ndb_word_writer_ctx
 {
 	struct ndb_txn *txn;
 	struct ndb_note *note;
 	uint64_t note_id;
 };
 
 static int ndb_fulltext_word_writer(void *ctx,
 		const char *word, int word_len, int words)
 {
 	struct ndb_word_writer_ctx *wctx = ctx;
 
 	if (!ndb_write_word_to_index(wctx->txn, word, word_len, words,
 				     wctx->note->created_at, wctx->note_id)) {
 		// too big to write this one, just skip it
 		ndb_debug("failed to write word '%.*s' to index\n", word_len, word);
 
 		return 0;
 	}
 
 	//fprintf(stderr, "wrote '%.*s' to note text index\n", word_len, word);
 	return 1;
 }
 
 static int ndb_write_note_fulltext_index(struct ndb_txn *txn,
 					 struct ndb_note *note,
 					 uint64_t note_id)
 {
 	struct cursor cur;
 	unsigned char *content;
 	struct ndb_str str;
 	struct ndb_word_writer_ctx ctx;
 
 	str = ndb_note_str(note, &note->content);
 	// I don't think this should happen?
 	if (unlikely(str.flag == NDB_PACKED_ID))
 		return 0;
 
 	content = (unsigned char *)str.str;
 
 	make_cursor(content, content + note->content_length, &cur);
 
 	ctx.txn = txn;
 	ctx.note = note;
 	ctx.note_id = note_id;
 
 	ndb_parse_words(&cur, &ctx, ndb_fulltext_word_writer);
 
 	return 1;
 }
 
 static int ndb_parse_search_words(void *ctx, const char *word_str, int word_len, int word_index)
 {
 	(void)word_index;
 	struct ndb_search_words *words = ctx;
 	struct ndb_word *word;
 
 	if (words->num_words + 1 > MAX_TEXT_SEARCH_WORDS)
 		return 0;
 
 	word = &words->words[words->num_words++];
 	word->word = word_str;
 	word->word_len = word_len;
 
 	return 1;
 }
 
 static void ndb_search_words_init(struct ndb_search_words *words)
 {
 	words->num_words = 0;
 }
 
 static int prefix_count(const char *str1, int len1, const char *str2, int len2) {
 	int i, count = 0;
 	int min_len = len1 < len2 ? len1 : len2;
 
 	for (i = 0; i < min_len; i++) {
 		// case insensitive
 		if (tolower(str1[i]) == tolower(str2[i]))
 			count++;
 		else
 			break;
 	}
 
 	return count;
 }
 
 static int ndb_prefix_matches(struct ndb_text_search_result *result,
 			      struct ndb_word *search_word)
 {
 	// Empty strings shouldn't happen but let's
 	if (result->key.str_len < 2 || search_word->word_len < 2)
 		return 0;
 
 	// make sure we at least have two matching prefix characters. exact
 	// matches are nice but range searches allow us to match prefixes as
 	// well. A double-char prefix is suffient, but maybe we could up this
 	// in the future.
 	//
 	// TODO: How are we handling utf-8 prefix matches like
 	// japanese?
 	//
 	if (   result->key.str[0] != tolower(search_word->word[0])
 	    && result->key.str[1] != tolower(search_word->word[1])
 	    )
 		return 0;
 
 	// count the number of prefix-matched characters. This will be used
 	// for ranking search results
 	result->prefix_chars = prefix_count(result->key.str,
 					    result->key.str_len,
 					    search_word->word,
 					    search_word->word_len);
 
 	if (result->prefix_chars <= (int)((double)search_word->word_len / 1.5))
 		return 0;
 
 	return 1;
 }
 
 // This is called when scanning the full text search index. Scanning stops
 // when we no longer have a prefix match for the word
 static int ndb_text_search_next_word(MDB_cursor *cursor, MDB_cursor_op op,
 	MDB_val *k, struct ndb_word *search_word,
 	struct ndb_text_search_result *last_result,
 	struct ndb_text_search_result *result,
 	MDB_cursor_op order_op)
 {
 	struct cursor key_cursor;
 	//struct ndb_text_search_key search_key;
 	MDB_val v;
 	int retries;
 	retries = -1;
 
 	make_cursor(k->mv_data, (unsigned char *)k->mv_data + k->mv_size, &key_cursor);
 
 	// When op is MDB_SET_RANGE, this initializes the search. Position
 	// the cursor at the next key greater than or equal to the specified
 	// key.
 	//
 	// Subsequent searches should use MDB_NEXT
 	if (mdb_cursor_get(cursor, k, &v, op)) {
 		// we should only do this if we're going in reverse
 		if (op == MDB_SET_RANGE && order_op == MDB_PREV) {
 			// if set range worked and our key exists, it should be
 			// the one right before this one
 			if (mdb_cursor_get(cursor, k, &v, MDB_PREV))
 				return 0;
 		} else {
 			return 0;
 		}
 	}
 
 retry:
 	retries++;
 	/*
 	printf("continuing from ");
 	if (ndb_unpack_text_search_key(k->mv_data, k->mv_size, &search_key)) {
 		ndb_print_text_search_key(&search_key);
 	} else { printf("??"); }
 	printf("\n");
 	*/
 
 	make_cursor(k->mv_data, (unsigned char *)k->mv_data + k->mv_size, &key_cursor);
 
 	if (unlikely(!ndb_unpack_text_search_key_noteid(&key_cursor, &result->key.note_id))) {
 		fprintf(stderr, "UNUSUAL: failed to unpack text search key note_id\n");
 		return 0;
 	}
 
 	// if the note id doesn't match the last result, then we stop trying
 	// each search word
 	if (last_result && last_result->key.note_id != result->key.note_id) {
 		return 0;
 	}
 
 	// On success, this could still be not related at all.
 	// It could just be adjacent to the word. Let's check
 	// if we have a matching prefix at least.
 
 	// Before we unpack the entire key, let's quickly
 	// unpack just the string to check the prefix. We don't
 	// need to unpack the entire key if the prefix doesn't
 	// match
 	if (!ndb_unpack_text_search_key_string(&key_cursor,
 					       &result->key.str,
 					       &result->key.str_len)) {
 		// this should never happen
 		fprintf(stderr, "UNUSUAL: failed to unpack text search key string\n");
 		return 0;
 	}
 
 	if (!ndb_prefix_matches(result, search_word)) {
 		/*
 		printf("result prefix '%.*s' didn't match search word '%.*s'\n",
 			result->key.str_len, result->key.str,
 			search_word->word_len, search_word->word);
 			*/
 		// we should only do this if we're going in reverse
 		if (retries == 0 && op == MDB_SET_RANGE && order_op == MDB_PREV) {
 			// if set range worked and our key exists, it should be
 			// the one right before this one
 			mdb_cursor_get(cursor, k, &v, MDB_PREV);
 			goto retry;
 		} else {
 			return 0;
 		}
 	}
 
 	// Unpack the remaining text search key, we will need this information
 	// when building up our search results.
 	if (!ndb_unpack_remaining_text_search_key(&key_cursor, &result->key)) {
 		// This should never happen
 		fprintf(stderr, "UNUSUAL: failed to unpack text search key\n");
 		return 0;
 	}
 
 			/*
 	if (last_result) {
 		if (result->key.word_index < last_result->key.word_index) {
 			fprintf(stderr, "skipping '%.*s' because it is before last result '%.*s'\n",
 					result->key.str_len, result->key.str,
 					last_result->key.str_len, last_result->key.str);
 			return 0;
 		}
 	}
 					*/
 
 	return 1;
 }
 
 static void ndb_text_search_results_init(
 		struct ndb_text_search_results *results) {
 	results->num_results = 0;
 }
 
 void ndb_default_text_search_config(struct ndb_text_search_config *cfg)
 {
 	cfg->order = NDB_ORDER_DESCENDING;
 	cfg->limit = MAX_TEXT_SEARCH_RESULTS;
 }
 
 void ndb_text_search_config_set_order(struct ndb_text_search_config *cfg,
 				     enum ndb_search_order order)
 {
 	cfg->order = order;
 }
 
 void ndb_text_search_config_set_limit(struct ndb_text_search_config *cfg, int limit)
 {
 	cfg->limit = limit;
 }
 
 static int compare_search_words(const void *pa, const void *pb)
 {
 	struct ndb_word *a, *b;
 
 	a = (struct ndb_word *)pa;
 	b = (struct ndb_word *)pb;
 
 	if (a->word_len == b->word_len) {
 		return 0;
 	} else if (a->word_len > b->word_len) {
 		// biggest words should be at the front of the list,
 		// so we say it's "smaller" here
 		return -1;
 	} else {
 		return 1;
 	}
 }
 
 // Sort search words from largest to smallest. Larger words are less likely
 // in the index, allowing our scan to walk fewer words at the root when
 // recursively matching.
 void sort_largest_to_smallest(struct ndb_search_words *words)
 {
 	qsort(words->words, words->num_words, sizeof(words->words[0]), compare_search_words);
 }
 
 
 int ndb_text_search_with(struct ndb_txn *txn, const char *query,
 		    struct ndb_text_search_results *results,
 		    struct ndb_text_search_config *config,
 		    struct ndb_filter *filter)
 {
 	unsigned char buffer[1024], *buf;
 	unsigned char saved_buf[1024], *saved;
 	struct ndb_text_search_result *result, *last_result;
 	struct ndb_text_search_result candidate, last_candidate;
 	struct ndb_search_words search_words;
 	//struct ndb_text_search_key search_key;
 	struct ndb_word *search_word;
 	struct ndb_note *note;
 	struct cursor cur;
 	uint64_t since, until, timestamp_op, *pint;
 	size_t note_size;
 	ndb_text_search_key_order_fn key_order_fn;
 	MDB_dbi text_db;
 	MDB_cursor *cursor;
 	MDB_val k, v;
 	int i, j, keysize, saved_size, limit;
 	MDB_cursor_op op, order_op;
 
 	note_size = 0;
 	note = 0;
 	saved = NULL;
 	ndb_text_search_results_init(results);
 	ndb_search_words_init(&search_words);
 
 	until = UINT64_MAX;
 	since = 0;
 	limit = MAX_TEXT_SEARCH_RESULTS;
 
 	// until, since from filter
 	if (filter != NULL) {
 		if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
 			until = *pint;
 
 		if ((pint = ndb_filter_get_int(filter, NDB_FILTER_SINCE)))
 			since = *pint;
 
 		if ((pint = ndb_filter_get_int(filter, NDB_FILTER_LIMIT)))
 			limit = *pint;
 	}
 
 	order_op = MDB_PREV;
 	key_order_fn = ndb_make_text_search_key_high;
 	timestamp_op = until;
 	if (config) {
 		if (config->order == NDB_ORDER_ASCENDING) {
 			order_op = MDB_NEXT;
 			// set the min timestamp value to since when ascending
 			timestamp_op = since;
 			key_order_fn = ndb_make_text_search_key_low;
 		}
 		limit = min(limit, config->limit);
 	}
 	// end search config
 
 	text_db = txn->lmdb->dbs[NDB_DB_NOTE_TEXT];
 	make_cursor((unsigned char *)query, (unsigned char *)query + strlen(query), &cur);
 
 	ndb_parse_words(&cur, &search_words, ndb_parse_search_words);
 	if (search_words.num_words == 0)
 		return 0;
 
 	if ((i = mdb_cursor_open(txn->mdb_txn, text_db, &cursor))) {
 		fprintf(stderr, "nd_text_search: mdb_cursor_open failed, error %d\n", i);
 		return 0;
 	}
 
 	// This should complete the query quicker because the larger words are
 	// likely to have fewer entries in the search index. This is not always
 	// true. Words with higher frequency (like bitcoin on nostr in 2024)
 	// may be slower. TODO: Skip word recursion by leveraging a minimal
 	// perfect hashmap of parsed words on a note
 	sort_largest_to_smallest(&search_words);
 
 	// for each word, we recursively find all of the submatches
 	while (results->num_results < limit) {
 		last_result = NULL;
 		result = &results->results[results->num_results];
 
 		// if we have saved, then we continue from the last root search
 		// sequence
 		if (saved) {
 			buf = saved_buf;
 			saved = NULL;
 			keysize = saved_size;
 
 			k.mv_data = buf;
 			k.mv_size = saved_size;
 
 			// reposition the cursor so we can continue
 			if (mdb_cursor_get(cursor, &k, &v, MDB_SET_RANGE))
 				break;
 
 			op = order_op;
 		} else {
 			// construct a packed fulltext search key using this
 			// word. This key doesn't contain any timestamp or index
 			// info, so it should range match instead of exact
 			// match
 			if (!key_order_fn(buffer, sizeof(buffer),
 					  search_words.words[0].word_len,
 					  search_words.words[0].word,
 					  timestamp_op,
 					  &keysize))
 			{
 				// word is too big to fit in 1024-sized key
 				continue;
 			}
 
 			buf = buffer;
 			op = MDB_SET_RANGE;
 		}
 
 		for (j = 0; j < search_words.num_words; j++) {
 			search_word = &search_words.words[j];
 
 			// shouldn't happen but let's be defensive a bit
 			if (search_word->word_len == 0)
 				continue;
 
 			// if we already matched a note in this phrase, make
 			// sure we're including the note id in the query
 			if (last_result) {
 				// we are narrowing down a search.
 				// if we already have this note id, just continue
 				for (i = 0; i < results->num_results; i++) {
 					if (results->results[i].key.note_id == last_result->key.note_id)
 						// we can't break here to
 						// leave the word loop so
 						// have to use a goto
 						goto cont;
 				}
 
 				if (!ndb_make_noted_text_search_key(
 					buffer, sizeof(buffer),
 					search_word->word_len,
 					search_word->word,
 					last_result->key.timestamp,
 					last_result->key.note_id,
 					&keysize))
 				{
 					continue;
 				}
 
 				buf = buffer;
 			}
 
 			k.mv_data = buf;
 			k.mv_size = keysize;
 
 			// TODO: we can speed this up with the minimal perfect
 			// hashmap by quickly rejecting the remaining words
 			// by looking in the word hashmap on the note. This
 			// would allow us to skip the recursive word lookup
 			// thing
 			if (!ndb_text_search_next_word(cursor, op, &k,
 						       search_word,
 						       last_result,
 						       &candidate,
 						       order_op)) {
 				// we didn't find a match for this note_id
 				if (j == 0)
 					// if we're at one of the root words,
 					// this means that there are no further
 					// root word matches for any note, so
 					// we know we're done
 					goto done;
 				else
 					break;
 			}
 
 			*result = candidate;
 			op = MDB_SET_RANGE;
 
 			// save the first key match, since we will continue from
 			// this on the next root word result
 			if (j == 0) {
 				if (!saved) {
 					memcpy(saved_buf, k.mv_data, k.mv_size);
 					saved = saved_buf;
 					saved_size = k.mv_size;
 				}
 
 				// since we will be trying to match the same
 				// note_id on all subsequent word matches,
 				// let's lookup this note and make sure it
 				// matches the filter if we have one. If it
 				// doesn't match, we can quickly skip the
 				// remaining word queries
 				if (filter) {
 					if ((note = ndb_get_note_by_key(txn,
 							result->key.note_id,
 							&note_size)))
 					{
 						if (!ndb_filter_matches(filter, note)) {
 							break;
 						}
 						result->note = note;
 						result->note_size = note_size;
 					}
 				}
 			}
 
 			result->note = note;
 			result->note_size = note_size;
 			last_candidate = *result;
 			last_result = &last_candidate;
 		}
 
 		// we matched all of the queries!
 		if (j == search_words.num_words) {
 			results->num_results++;
 		}
 
 cont:
 		;
 	}
 
 done:
 	mdb_cursor_close(cursor);
 
 	return 1;
 }
 
 int ndb_text_search(struct ndb_txn *txn, const char *query,
 		    struct ndb_text_search_results *results,
 		    struct ndb_text_search_config *config)
 {
 	return ndb_text_search_with(txn, query, results, config, NULL);
 }
 
 static void ndb_write_blocks(struct ndb_txn *txn, uint64_t note_key,
 			     struct ndb_blocks *blocks)
 {
 	int rc;
 	MDB_val key, val;
 
 	// make sure we're not writing the owned flag to the db
 	blocks->flags &= ~NDB_BLOCK_FLAG_OWNED;
 
 	key.mv_data = &note_key;
 	key.mv_size = sizeof(note_key);
 	val.mv_data = blocks;
 	val.mv_size = ndb_blocks_total_size(blocks);
 	assert((val.mv_size % 8) == 0);
 
 	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_BLOCKS], &key, &val, 0))) {
 		ndb_debug("write version to note_blocks failed: %s\n",
 				mdb_strerror(rc));
 		return;
 	}
 }
 
 static int ndb_write_new_blocks(struct ndb_txn *txn, struct ndb_note *note,
 				uint64_t note_key, unsigned char *scratch,
 				size_t scratch_size)
 {
 	size_t content_len;
 	const char *content;
 	struct ndb_blocks *blocks;
 
 	content_len = ndb_note_content_length(note);
 	content = ndb_note_content(note);
 
 	if (!ndb_parse_content(scratch, scratch_size, content, content_len, &blocks)) {
 		//ndb_debug("failed to parse content '%.*s'\n", content_len, content);
 		return 0;
 	}
 
 	ndb_write_blocks(txn, note_key, blocks);
 	return 1;
 }
 
 static uint64_t ndb_write_note(struct ndb_txn *txn,
 			       struct ndb_writer_note *note,
 			       unsigned char *scratch, size_t scratch_size,
 			       uint32_t ndb_flags)
 {
 	int rc, relay_len = 0;
 	uint64_t note_key, kind;
 	MDB_dbi note_db;
 	MDB_val key, val;
 
 	kind = note->note->kind;
 
 	// let's quickly sanity check if we already have this note
 	if (ndb_get_notekey_by_id(txn, note->note->id))
 		return 0;
 
 	// get dbs
 	note_db = txn->lmdb->dbs[NDB_DB_NOTE];
 
 	// get new key
 	note_key = ndb_get_last_key(txn->mdb_txn, note_db) + 1;
 
 	// write note to event store
 	key.mv_data = &note_key;
 	key.mv_size = sizeof(note_key);
 	val.mv_data = note->note;
 	val.mv_size = note->note_len;
 
 	if ((rc = mdb_put(txn->mdb_txn, note_db, &key, &val, 0))) {
 		ndb_debug("write note to db failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 
 	if (note->relay != NULL)
 		relay_len = strlen(note->relay);
 
 	ndb_write_note_id_index(txn, note->note, note_key);
 	ndb_write_note_kind_index(txn, note->note, note_key);
 	ndb_write_note_tag_index(txn, note->note, note_key);
 	ndb_write_note_pubkey_index(txn, note->note, note_key);
 	ndb_write_note_pubkey_kind_index(txn, note->note, note_key);
 	ndb_write_note_relay_kind_index(txn, kind, note_key,
 					ndb_note_created_at(note->note),
 					note->relay, relay_len);
 	ndb_write_note_relay(txn, note_key, note->relay, relay_len);
 
 	// only parse content and do fulltext index on text and longform notes
 	if (kind == 1 || kind == 30023) {
 		if (!ndb_flag_set(ndb_flags, NDB_FLAG_NO_FULLTEXT)) {
 			if (!ndb_write_note_fulltext_index(txn, note->note, note_key))
 				return 0;
 		}
 
 		// write note blocks
 		if (!ndb_flag_set(ndb_flags, NDB_FLAG_NO_NOTE_BLOCKS)) {
 			ndb_write_new_blocks(txn, note->note, note_key, scratch, scratch_size);
 		}
 	} else if (kind == 7 && !ndb_flag_set(ndb_flags, NDB_FLAG_NO_STATS)) {
 		ndb_write_reaction_stats(txn, note->note);
 	}
 
 	return note_key;
 }
 
 static void ndb_monitor_lock(struct ndb_monitor *mon) {
 	pthread_mutex_lock(&mon->mutex);
 }
 
 static void ndb_monitor_unlock(struct ndb_monitor *mon) {
 	pthread_mutex_unlock(&mon->mutex);
 }
 
 struct written_note {
 	uint64_t note_id;
 	struct ndb_writer_note *note;
 };
 
 // When the data has been committed to the database, take all of the written
 // notes, check them against subscriptions, and then write to the subscription
 // inbox for all matching notes
 static void ndb_notify_subscriptions(struct ndb_monitor *monitor,
 				     struct written_note *wrote, int num_notes)
 {
 	int i, k;
 	int pushed;
 	struct written_note *written;
 	struct ndb_note *note;
 	struct ndb_subscription *sub;
 
 	ndb_monitor_lock(monitor);
 
 	for (i = 0; i < monitor->num_subscriptions; i++) {
 		sub = &monitor->subscriptions[i];
 		ndb_debug("checking subscription %d, %d notes\n", i, num_notes);
 
 		pushed = 0;
 		for (k = 0; k < num_notes; k++) {
 			written = &wrote[k];
 			note = written->note->note;
 
 			if (ndb_filter_group_matches(&sub->group, note)) {
 				ndb_debug("pushing note\n");
 
 				if (!prot_queue_push(&sub->inbox, &written->note_id)) {
 					ndb_debug("couldn't push note to subscriber");
 				} else {
 					pushed++;
 				}
 			} else {
 				ndb_debug("not pushing note\n");
 			}
 		}
 
 		// After pushing all of the matching notes, check to see if we
 		// have a registered subscription callback. If so, we call it.
 		// The callback needs to call ndb_poll_for_notes to pull data
 		// that was just pushed to the queue in the for loop above.
 		if (monitor->sub_cb != NULL && pushed > 0) {
 			monitor->sub_cb(monitor->sub_cb_ctx, sub->subid);
 		}
 	}
 
 	ndb_monitor_unlock(monitor);
 }
 
 uint64_t ndb_write_note_and_profile(
 		struct ndb_txn *txn,
 		struct ndb_writer_profile *profile,
 		unsigned char *scratch,
 		size_t scratch_size,
 		uint32_t ndb_flags)
 {
 	uint64_t note_nkey;
 
 	note_nkey = ndb_write_note(txn, &profile->note, scratch, scratch_size, ndb_flags);
 
 	if (profile->record.builder) {
 		// only write if parsing didn't fail
 		ndb_write_profile(txn, profile, note_nkey);
 	}
 
 	return note_nkey;
 }
 
 // only to be called from the writer thread
 static int ndb_write_version(struct ndb_txn *txn, uint64_t version)
 {
 	int rc;
 	MDB_val key, val;
 	uint64_t version_key;
 
 	version_key = NDB_META_KEY_VERSION;
 
 	key.mv_data = &version_key;
 	key.mv_size = sizeof(version_key);
 	val.mv_data = &version;
 	val.mv_size = sizeof(version);
 
 	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NDB_META], &key, &val, 0))) {
 		ndb_debug("write version to ndb_meta failed: %s\n",
 				mdb_strerror(rc));
 		return 0;
 	}
 
 	//fprintf(stderr, "writing version %" PRIu64 "\n", version);
 	return 1;
 }
 
 
 static int ndb_run_migrations(struct ndb_txn *txn)
 {
 	int64_t version, latest_version, i;
 
 	latest_version = sizeof(MIGRATIONS) / sizeof(MIGRATIONS[0]);
 
 	if ((version = ndb_db_version(txn)) == -1) {
 		ndb_debug("run_migrations: no version found, assuming new db\n");
 		version = latest_version;
 
 		// no version found. fresh db?
 		if (!ndb_write_version(txn, version)) {
 			fprintf(stderr, "run_migrations: failed writing db version");
 			return 0;
 		}
 
 		return 1;
 	} else {
 		ndb_debug("ndb: version %" PRIu64 " found\n", version);
 	}
 
 	if (version < latest_version)
 		fprintf(stderr, "nostrdb: migrating v%d -> v%d\n",
 				(int)version, (int)latest_version);
 
 	for (i = version; i < latest_version; i++) {
 		if (!MIGRATIONS[i].fn(txn)) {
 			fprintf(stderr, "run_migrations: migration v%d -> v%d failed\n", (int)i, (int)(i+1));
 			return 0;
 		}
 
 		if (!ndb_write_version(txn, i+1)) {
 			fprintf(stderr, "run_migrations: failed writing db version");
 			return 0;
 		}
 
 		version = i+1;
 	}
 
 	return 1;
 }
 
 
 static void *ndb_writer_thread(void *data)
 {
 	ndb_debug("started writer thread\n");
 	struct ndb_writer *writer = data;
 	struct ndb_writer_msg msgs[THREAD_QUEUE_BATCH], *msg;
 	struct written_note written_notes[THREAD_QUEUE_BATCH];
 	int i, popped, done, relay_len, needs_commit, num_notes;
 	uint64_t note_nkey;
 	struct ndb_txn txn;
 	unsigned char *scratch;
 
 	// 2MB scratch buffer for parsing note content
 	scratch = malloc(writer->scratch_size);
 	MDB_txn *mdb_txn = NULL;
 	ndb_txn_from_mdb(&txn, writer->lmdb, mdb_txn);
 
 	done = 0;
 	while (!done) {
 		txn.mdb_txn = NULL;
 		num_notes = 0;
 		ndb_debug("writer waiting for items\n");
 		popped = prot_queue_pop_all(&writer->inbox, msgs, THREAD_QUEUE_BATCH);
 		ndb_debug("writer popped %d items\n", popped);
 
 		needs_commit = 0;
 		for (i = 0 ; i < popped; i++) {
 			msg = &msgs[i];
 			switch (msg->type) {
 			case NDB_WRITER_NOTE: needs_commit = 1; break;
 			case NDB_WRITER_PROFILE: needs_commit = 1; break;
 			case NDB_WRITER_DBMETA: needs_commit = 1; break;
 			case NDB_WRITER_PROFILE_LAST_FETCH: needs_commit = 1; break;
 			case NDB_WRITER_BLOCKS: needs_commit = 1; break;
 			case NDB_WRITER_MIGRATE: needs_commit = 1; break;
 			case NDB_WRITER_NOTE_RELAY: needs_commit = 1; break;
 			case NDB_WRITER_QUIT: break;
 			}
 		}
 
 		if (needs_commit && mdb_txn_begin(txn.lmdb->env, NULL, 0, (MDB_txn **)&txn.mdb_txn))
 		{
 			fprintf(stderr, "writer thread txn_begin failed");
 			// should definitely not happen unless DB is full
 			// or something ?
 			continue;
 		}
 
 		for (i = 0; i < popped; i++) {
 			msg = &msgs[i];
 
 			switch (msg->type) {
 			case NDB_WRITER_QUIT:
 				// quits are handled before this
 				ndb_debug("writer thread got quit message\n");
 				done = 1;
 				continue;
 			case NDB_WRITER_PROFILE:
 				note_nkey =
 					ndb_write_note_and_profile(
 						&txn,
 						&msg->profile,
 						scratch,
 						writer->scratch_size,
 						writer->ndb_flags);
 
 				if (note_nkey > 0) {
 					written_notes[num_notes++] =
 					(struct written_note){
 						.note_id = note_nkey,
 						.note = &msg->profile.note,
 					};
 				} else {
 					ndb_debug("failed to write note\n");
 				}
 				break;
 			case NDB_WRITER_NOTE:
 				note_nkey = ndb_write_note(&txn, &msg->note,
 							   scratch,
 							   writer->scratch_size,
 							   writer->ndb_flags);
 
 				if (note_nkey > 0) {
 					written_notes[num_notes++] = (struct written_note){
 						.note_id = note_nkey,
 						.note = &msg->note,
 					};
 				}
 				break;
 			case NDB_WRITER_NOTE_RELAY:
 				relay_len = strlen(msg->note_relay.relay);
 				ndb_write_note_relay(&txn,
 						     msg->note_relay.note_key,
 						     msg->note_relay.relay,
 						     relay_len);
 				ndb_write_note_relay_kind_index(
 					&txn,
 					msg->note_relay.kind,
 					msg->note_relay.note_key,
 					msg->note_relay.created_at,
 					msg->note_relay.relay,
 					relay_len);
 				break;
 			case NDB_WRITER_DBMETA:
 				ndb_write_version(&txn, msg->ndb_meta.version);
 				break;
 			case NDB_WRITER_BLOCKS:
 				ndb_write_blocks(&txn, msg->blocks.note_key,
 						       msg->blocks.blocks);
 				break;
 			case NDB_WRITER_MIGRATE:
 				if (!ndb_run_migrations(&txn)) {
 					mdb_txn_abort(txn.mdb_txn);
 					goto bail;
 				}
 				break;
 			case NDB_WRITER_PROFILE_LAST_FETCH:
 				ndb_writer_last_profile_fetch(&txn,
 						msg->last_fetch.pubkey,
 						msg->last_fetch.fetched_at
 						);
 				break;
 			}
 		}
 
 		// commit writes
 		if (needs_commit) {
 			if (!ndb_end_query(&txn)) {
 				ndb_debug("writer thread txn commit failed\n");
 			} else {
 				ndb_debug("notifying subscriptions, %d notes\n", num_notes);
 				ndb_notify_subscriptions(writer->monitor,
 							 written_notes,
 							 num_notes);
 				// update subscriptions
 			}
 		}
 
 		// free notes
 		for (i = 0; i < popped; i++) {
 			msg = &msgs[i];
 			if (msg->type == NDB_WRITER_NOTE) {
 				free(msg->note.note);
 				if (msg->note.relay)
 					free((void*)msg->note.relay);
 			} else if (msg->type == NDB_WRITER_PROFILE) {
 				free(msg->profile.note.note);
 				//ndb_profile_record_builder_free(&msg->profile.record);
 			} else if (msg->type == NDB_WRITER_BLOCKS) {
 				ndb_blocks_free(msg->blocks.blocks);
 			} else if (msg->type == NDB_WRITER_NOTE_RELAY) {
 				free((void*)msg->note_relay.relay);
 			}
 		}
 	}
 
 bail:
 	free(scratch);
 	ndb_debug("quitting writer thread\n");
 	return NULL;
 }
 
 static void *ndb_ingester_thread(void *data)
 {
 	secp256k1_context *ctx;
 	struct thread *thread = data;
 	struct ndb_ingester *ingester = (struct ndb_ingester *)thread->ctx;
 	struct ndb_lmdb *lmdb = ingester->lmdb;
 	struct ndb_ingester_msg msgs[THREAD_QUEUE_BATCH], *msg;
 	struct ndb_writer_msg outs[THREAD_QUEUE_BATCH], *out;
 	int i, to_write, popped, done, any_event;
 	MDB_txn *read_txn = NULL;
 	int rc;
 
 	ctx = secp256k1_context_create(SECP256K1_CONTEXT_VERIFY);
 	ndb_debug("started ingester thread\n");
 
 	done = 0;
 	while (!done) {
 		to_write = 0;
 		any_event = 0;
 
 		popped = prot_queue_pop_all(&thread->inbox, msgs, THREAD_QUEUE_BATCH);
 		ndb_debug("ingester popped %d items\n", popped);
 
 		for (i = 0; i < popped; i++) {
 			msg = &msgs[i];
 			if (msg->type == NDB_INGEST_EVENT) {
 				any_event = 1;
 				break;
 			}
 		}
 
 		if (any_event && (rc = mdb_txn_begin(lmdb->env, NULL, MDB_RDONLY, &read_txn))) {
 			// this is bad
 			fprintf(stderr, "UNUSUAL ndb_ingester: mdb_txn_begin failed: '%s'\n",
 					mdb_strerror(rc));
 			continue;
 		}
 
 		for (i = 0; i < popped; i++) {
 			msg = &msgs[i];
 			switch (msg->type) {
 			case NDB_INGEST_QUIT:
 				done = 1;
 				break;
 
 			case NDB_INGEST_EVENT:
 				out = &outs[to_write];
 				if (ndb_ingester_process_event(ctx, ingester,
 							       &msg->event, out,
 							       read_txn)) {
 					to_write++;
 				}
 			}
 		}
 
 		if (any_event)
 			mdb_txn_abort(read_txn);
 
 		if (to_write > 0) {
 			ndb_debug("pushing %d events to write queue\n", to_write);
 			if (!prot_queue_push_all(ingester->writer_inbox, outs, to_write)) {
 				ndb_debug("failed pushing %d events to write queue\n", to_write);
 			}
 		}
 	}
 
 	ndb_debug("quitting ingester thread\n");
 	secp256k1_context_destroy(ctx);
 	return NULL;
 }
 
 
 static int ndb_writer_init(struct ndb_writer *writer, struct ndb_lmdb *lmdb,
 			   struct ndb_monitor *monitor, uint32_t ndb_flags,
 			   int scratch_size)
 {
 	writer->lmdb = lmdb;
 	writer->monitor = monitor;
 	writer->ndb_flags = ndb_flags;
 	writer->scratch_size = scratch_size;
 	writer->queue_buflen = sizeof(struct ndb_writer_msg) * DEFAULT_QUEUE_SIZE;
 	writer->queue_buf = malloc(writer->queue_buflen);
 	if (writer->queue_buf == NULL) {
 		fprintf(stderr, "ndb: failed to allocate space for writer queue");
 		return 0;
 	}
 
 	// init the writer queue.
 	prot_queue_init(&writer->inbox, writer->queue_buf,
 			writer->queue_buflen, sizeof(struct ndb_writer_msg));
 
 	// spin up the writer thread
 	if (THREAD_CREATE(writer->thread_id, ndb_writer_thread, writer))
 	{
 		fprintf(stderr, "ndb writer thread failed to create\n");
 		return 0;
 	}
 
 	return 1;
 }
 
 // initialize the ingester queue and then spawn the thread
 static int ndb_ingester_init(struct ndb_ingester *ingester,
 			     struct ndb_lmdb *lmdb,
 			     struct prot_queue *writer_inbox,
 			     const struct ndb_config *config)
 {
 	int elem_size, num_elems;
 	static struct ndb_ingester_msg quit_msg = { .type = NDB_INGEST_QUIT };
 
 	// TODO: configurable queue sizes
 	elem_size = sizeof(struct ndb_ingester_msg);
 	num_elems = DEFAULT_QUEUE_SIZE;
 
 	ingester->writer_inbox = writer_inbox;
 	ingester->lmdb = lmdb;
 	ingester->flags = config->flags;
 	ingester->filter = config->ingest_filter;
 	ingester->filter_context = config->filter_context;
 
 	if (!threadpool_init(&ingester->tp, config->ingester_threads,
 			     elem_size, num_elems, &quit_msg, ingester,
 			     ndb_ingester_thread))
 	{
 		fprintf(stderr, "ndb ingester threadpool failed to init\n");
 		return 0;
 	}
 
 	return 1;
 }
 
 static int ndb_writer_destroy(struct ndb_writer *writer)
 {
 	struct ndb_writer_msg msg;
 
 	// kill thread
 	msg.type = NDB_WRITER_QUIT;
 	ndb_debug("writer: pushing quit message\n");
 	if (!prot_queue_push(&writer->inbox, &msg)) {
 		// queue is too full to push quit message. just kill it.
 		ndb_debug("writer: terminating thread\n");
 		THREAD_TERMINATE(writer->thread_id);
 	} else {
 		ndb_debug("writer: joining thread\n");
 		THREAD_FINISH(writer->thread_id);
 	}
 
 	// cleanup
 	ndb_debug("writer: cleaning up protected queue\n");
 	prot_queue_destroy(&writer->inbox);
 
 	free(writer->queue_buf);
 
 	return 1;
 }
 
 static int ndb_ingester_destroy(struct ndb_ingester *ingester)
 {
 	threadpool_destroy(&ingester->tp);
 	return 1;
 }
 
 static int ndb_init_lmdb(const char *filename, struct ndb_lmdb *lmdb, size_t mapsize)
 {
 	int rc;
 	MDB_txn *txn;
 
 	if ((rc = mdb_env_create(&lmdb->env))) {
 		fprintf(stderr, "mdb_env_create failed, error %d\n", rc);
 		return 0;
 	}
 
 	if ((rc = mdb_env_set_mapsize(lmdb->env, mapsize))) {
 		fprintf(stderr, "mdb_env_set_mapsize failed, error %d\n", rc);
 		return 0;
 	}
 
 	if ((rc = mdb_env_set_maxdbs(lmdb->env, NDB_DBS))) {
 		fprintf(stderr, "mdb_env_set_maxdbs failed, error %d\n", rc);
 		return 0;
 	}
 
 	if ((rc = mdb_env_open(lmdb->env, filename, 0, 0664))) {
 		fprintf(stderr, "mdb_env_open failed, error %d\n", rc);
 		return 0;
 	}
 
 	// Initialize DBs
 	if ((rc = mdb_txn_begin(lmdb->env, NULL, 0, &txn))) {
 		fprintf(stderr, "mdb_txn_begin failed, error %d\n", rc);
 		return 0;
 	}
 
 	// note flatbuffer db
 	if ((rc = mdb_dbi_open(txn, "note", MDB_CREATE | MDB_INTEGERKEY, &lmdb->dbs[NDB_DB_NOTE]))) {
 		fprintf(stderr, "mdb_dbi_open event failed, error %d\n", rc);
 		return 0;
 	}
 
 	// note metadata db
 	if ((rc = mdb_dbi_open(txn, "meta", MDB_CREATE, &lmdb->dbs[NDB_DB_META]))) {
 		fprintf(stderr, "mdb_dbi_open meta failed, error %d\n", rc);
 		return 0;
 	}
 
 	// profile flatbuffer db
 	if ((rc = mdb_dbi_open(txn, "profile", MDB_CREATE | MDB_INTEGERKEY, &lmdb->dbs[NDB_DB_PROFILE]))) {
 		fprintf(stderr, "mdb_dbi_open profile failed, error %d\n", rc);
 		return 0;
 	}
 
 	// profile search db
 	if ((rc = mdb_dbi_open(txn, "profile_search", MDB_CREATE, &lmdb->dbs[NDB_DB_PROFILE_SEARCH]))) {
 		fprintf(stderr, "mdb_dbi_open profile_search failed, error %d\n", rc);
 		return 0;
 	}
 	mdb_set_compare(txn, lmdb->dbs[NDB_DB_PROFILE_SEARCH], ndb_search_key_cmp);
 
 	// ndb metadata (db version, etc)
 	if ((rc = mdb_dbi_open(txn, "ndb_meta", MDB_CREATE | MDB_INTEGERKEY, &lmdb->dbs[NDB_DB_NDB_META]))) {
 		fprintf(stderr, "mdb_dbi_open ndb_meta failed, error %d\n", rc);
 		return 0;
 	}
 
 	// profile last fetches
 	if ((rc = mdb_dbi_open(txn, "profile_last_fetch", MDB_CREATE, &lmdb->dbs[NDB_DB_PROFILE_LAST_FETCH]))) {
 		fprintf(stderr, "mdb_dbi_open profile last fetch, error %d\n", rc);
 		return 0;
 	}
 
 	// relay kind index. maps <relay_url><kind><created><note_id> primary keys to relay records
 	// see ndb_relay_kind_cmp function for more details on the key format
 	if ((rc = mdb_dbi_open(txn, "relay_kind", MDB_CREATE, &lmdb->dbs[NDB_DB_NOTE_RELAY_KIND]))) {
 		fprintf(stderr, "mdb_dbi_open profile last fetch, error %d\n", rc);
 		return 0;
 	}
 	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_RELAY_KIND], ndb_relay_kind_cmp);
 
 	// note_id -> relay index
 	if ((rc = mdb_dbi_open(txn, "note_relays", MDB_CREATE | MDB_DUPSORT | MDB_DUPFIXED, &lmdb->dbs[NDB_DB_NOTE_RELAYS]))) {
 		fprintf(stderr, "mdb_dbi_open profile last fetch, error %d\n", rc);
 		return 0;
 	}
 
 	// id+ts index flags
 	unsigned int tsid_flags = MDB_CREATE | MDB_DUPSORT | MDB_DUPFIXED;
 
 	// index dbs
 	if ((rc = mdb_dbi_open(txn, "note_id", tsid_flags, &lmdb->dbs[NDB_DB_NOTE_ID]))) {
 		fprintf(stderr, "mdb_dbi_open id failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_ID], ndb_tsid_compare);
 
 	if ((rc = mdb_dbi_open(txn, "profile_pk", tsid_flags, &lmdb->dbs[NDB_DB_PROFILE_PK]))) {
 		fprintf(stderr, "mdb_dbi_open profile_pk failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 	mdb_set_compare(txn, lmdb->dbs[NDB_DB_PROFILE_PK], ndb_tsid_compare);
 
 	if ((rc = mdb_dbi_open(txn, "note_kind",
 			       MDB_CREATE | MDB_DUPSORT | MDB_INTEGERDUP | MDB_DUPFIXED,
 			       &lmdb->dbs[NDB_DB_NOTE_KIND]))) {
 		fprintf(stderr, "mdb_dbi_open note_kind failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_KIND], ndb_u64_ts_compare);
 
 	if ((rc = mdb_dbi_open(txn, "note_pubkey",
 			       MDB_CREATE | MDB_DUPSORT | MDB_INTEGERDUP | MDB_DUPFIXED,
 			       &lmdb->dbs[NDB_DB_NOTE_PUBKEY]))) {
 		fprintf(stderr, "mdb_dbi_open note_pubkey failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_PUBKEY], ndb_tsid_compare);
 
 	if ((rc = mdb_dbi_open(txn, "note_pubkey_kind",
 			       MDB_CREATE | MDB_DUPSORT | MDB_INTEGERDUP | MDB_DUPFIXED,
 			       &lmdb->dbs[NDB_DB_NOTE_PUBKEY_KIND]))) {
 		fprintf(stderr, "mdb_dbi_open note_pubkey_kind failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_PUBKEY_KIND], ndb_id_u64_ts_compare);
 
 	if ((rc = mdb_dbi_open(txn, "note_text", MDB_CREATE | MDB_DUPSORT,
 			       &lmdb->dbs[NDB_DB_NOTE_TEXT]))) {
 		fprintf(stderr, "mdb_dbi_open note_text failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_TEXT], ndb_text_search_key_compare);
 
 	if ((rc = mdb_dbi_open(txn, "note_blocks", MDB_CREATE | MDB_INTEGERKEY,
 			       &lmdb->dbs[NDB_DB_NOTE_BLOCKS]))) {
 		fprintf(stderr, "mdb_dbi_open note_blocks failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 
 	if ((rc = mdb_dbi_open(txn, "note_tags", MDB_CREATE | MDB_DUPSORT | MDB_DUPFIXED,
 			       &lmdb->dbs[NDB_DB_NOTE_TAGS]))) {
 		fprintf(stderr, "mdb_dbi_open note_tags failed: %s\n", mdb_strerror(rc));
 		return 0;
 	}
 	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_TAGS], ndb_tag_key_compare);
 
 	// Commit the transaction
 	if ((rc = mdb_txn_commit(txn))) {
 		fprintf(stderr, "mdb_txn_commit failed, error %d\n", rc);
 		return 0;
 	}
 
 	return 1;
 }
 
 static int ndb_queue_write_version(struct ndb *ndb, uint64_t version)
 {
 	struct ndb_writer_msg msg;
 	msg.type = NDB_WRITER_DBMETA;
 	msg.ndb_meta.version = version;
 	return ndb_writer_queue_msg(&ndb->writer, &msg);
 }
 
 static void ndb_monitor_init(struct ndb_monitor *monitor, ndb_sub_fn cb,
 			     void *sub_cb_ctx)
 {
 	monitor->num_subscriptions = 0;
 	monitor->sub_cb = cb;
 	monitor->sub_cb_ctx = sub_cb_ctx;
 	pthread_mutex_init(&monitor->mutex, NULL);
 }
 
 void ndb_filter_group_destroy(struct ndb_filter_group *group)
 {
 	struct ndb_filter *filter;
 	int i;
 	for (i = 0; i < group->num_filters; i++) {
 		filter = &group->filters[i];
 		ndb_filter_destroy(filter);
 	}
 }
 
 static void ndb_subscription_destroy(struct ndb_subscription *sub)
 {
 	ndb_filter_group_destroy(&sub->group);
 	// this was malloc'd inside ndb_subscribe
 	free(sub->inbox.buf);
 	prot_queue_destroy(&sub->inbox);
 	sub->subid = 0;
 }
 
 static void ndb_monitor_destroy(struct ndb_monitor *monitor)
 {
 	int i;
 
 	ndb_monitor_lock(monitor);
 
 	for (i = 0; i < monitor->num_subscriptions; i++) {
 		ndb_subscription_destroy(&monitor->subscriptions[i]);
 	}
 
 	monitor->num_subscriptions = 0;
 
 	ndb_monitor_unlock(monitor);
 
 	pthread_mutex_destroy(&monitor->mutex);
 }
 
 int ndb_init(struct ndb **pndb, const char *filename, const struct ndb_config *config)
 {
 	struct ndb *ndb;
 	//MDB_dbi ind_id; // TODO: ind_pk, etc
 
 	ndb = *pndb = calloc(1, sizeof(struct ndb));
 	ndb->flags = config->flags;
 
 	if (ndb == NULL) {
 		fprintf(stderr, "ndb_init: malloc failed\n");
 		return 0;
 	}
 
 	if (!ndb_init_lmdb(filename, &ndb->lmdb, config->mapsize))
 		return 0;
 
 	ndb_monitor_init(&ndb->monitor, config->sub_cb, config->sub_cb_ctx);
 
 	if (!ndb_writer_init(&ndb->writer, &ndb->lmdb, &ndb->monitor, ndb->flags,
 			     config->writer_scratch_buffer_size)) {
 		fprintf(stderr, "ndb_writer_init failed\n");
 		return 0;
 	}
 
 	if (!ndb_ingester_init(&ndb->ingester, &ndb->lmdb, &ndb->writer.inbox, config)) {
 		fprintf(stderr, "failed to initialize %d ingester thread(s)\n",
 				config->ingester_threads);
 		return 0;
 	}
 
 	if (!ndb_flag_set(config->flags, NDB_FLAG_NOMIGRATE)) {
 		struct ndb_writer_msg msg = { .type = NDB_WRITER_MIGRATE };
 		ndb_writer_queue_msg(&ndb->writer, &msg);
 	}
 
 	// Initialize LMDB environment and spin up threads
 	return 1;
 }
 
 void ndb_destroy(struct ndb *ndb)
 {
 	if (ndb == NULL)
 		return;
 
 	// ingester depends on writer and must be destroyed first
 	ndb_debug("destroying ingester\n");
 	ndb_ingester_destroy(&ndb->ingester);
 	ndb_debug("destroying writer\n");
 	ndb_writer_destroy(&ndb->writer);
 	ndb_debug("destroying monitor\n");
 	ndb_monitor_destroy(&ndb->monitor);
 
 	ndb_debug("closing env\n");
 	mdb_env_close(ndb->lmdb.env);
 
 	ndb_debug("ndb destroyed\n");
 	free(ndb);
 }
 
 
 // Process a nostr event from a client
 //
 // ie: ["EVENT", {"content":"..."} ...]
 //
 // The client-sent variation of ndb_process_event
 int ndb_process_client_event(struct ndb *ndb, const char *json, int len)
 {
 	struct ndb_ingest_meta meta;
 	ndb_ingest_meta_init(&meta, 1, NULL);
 
 	return ndb_ingest_event(&ndb->ingester, json, len, &meta);
 }
 
 // Process anostr event from a relay,
 //
 // ie: ["EVENT", "subid", {"content":"..."}...]
 //
 // This function returns as soon as possible, first copying the passed
 // json and then queueing it up for processing. Worker threads then take
 // the json and process it.
 //
 // Processing:
 //
 // 1. The event is parsed into ndb_notes and the signature is validated
 // 2. A quick lookup is made on the database to see if we already have
 //    the note id, if we do we don't need to waste time on json parsing
 //    or note validation.
 // 3. Once validation is done we pass it to the writer queue for writing
 //    to LMDB.
 //
 int ndb_process_event(struct ndb *ndb, const char *json, int json_len)
 {
 	struct ndb_ingest_meta meta;
 	ndb_ingest_meta_init(&meta, 0, NULL);
 
 	return ndb_ingest_event(&ndb->ingester, json, json_len, &meta);
 }
 
 int ndb_process_event_with(struct ndb *ndb, const char *json, int json_len,
 			   struct ndb_ingest_meta *meta)
 {
 	return ndb_ingest_event(&ndb->ingester, json, json_len, meta);
 }
 
 int _ndb_process_events(struct ndb *ndb, const char *ldjson, size_t json_len,
 			struct ndb_ingest_meta *meta)
 {
 	const char *start, *end, *very_end;
 	start = ldjson;
 	end = start + json_len;
 	very_end = ldjson + json_len;
 #if DEBUG
 	int processed = 0;
 #endif
 
 	while ((end = fast_strchr(start, '\n', very_end - start))) {
 		//printf("processing '%.*s'\n", (int)(end-start), start);
 		if (!ndb_process_event_with(ndb, start, end - start, meta)) {
 			ndb_debug("ndb_process_client_event failed\n");
 			return 0;
 		}
 		start = end + 1;
 #if DEBUG
 		processed++;
 #endif
 	}
 
 #if DEBUG
 	ndb_debug("ndb_process_events: processed %d events\n", processed);
 #endif
 
 	return 1;
 }
 
 #ifndef _WIN32
 // TODO: windows
 int ndb_process_events_stream(struct ndb *ndb, FILE* fp)
 {
 	char *line = NULL;
 	size_t len = 0;
 	ssize_t nread;
 
 	while ((nread = getline(&line, &len, fp)) != -1) {
 		if (line == NULL)
 			break;
 		ndb_process_event(ndb, line, len);
 	}
 
 	if (line)
 		free(line);
 
 	return 1;
 }
 #endif
 
 int ndb_process_events_with(struct ndb *ndb, const char *ldjson, size_t json_len,
 			    struct ndb_ingest_meta *meta)
 {
 	return _ndb_process_events(ndb, ldjson, json_len, meta);
 }
 
 int ndb_process_client_events(struct ndb *ndb, const char *ldjson, size_t json_len)
 {
 	struct ndb_ingest_meta meta;
 	ndb_ingest_meta_init(&meta, 1, NULL);
 
 	return _ndb_process_events(ndb, ldjson, json_len, &meta);
 }
 
 int ndb_process_events(struct ndb *ndb, const char *ldjson, size_t json_len)
 {
 	struct ndb_ingest_meta meta;
 	ndb_ingest_meta_init(&meta, 0, NULL);
 
 	return _ndb_process_events(ndb, ldjson, json_len, &meta);
 }
 
 static inline int cursor_push_tag(struct cursor *cur, struct ndb_tag *tag)
 {
 	return cursor_push_u16(cur, tag->count);
 }
 
 int ndb_builder_init(struct ndb_builder *builder, unsigned char *buf,
 		     size_t bufsize)
 {
 	struct ndb_note *note;
 	int half, size, str_indices_size;
 
 	// come on bruh
 	if (bufsize < sizeof(struct ndb_note) * 2)
 		return 0;
 
 	str_indices_size = bufsize / 32;
 	size = bufsize - str_indices_size;
 	half = size / 2;
 
 	//debug("size %d half %d str_indices %d\n", size, half, str_indices_size);
 
 	// make a safe cursor of our available memory
 	make_cursor(buf, buf + bufsize, &builder->mem);
 
 	note = builder->note = (struct ndb_note *)buf;
 
 	// take slices of the memory into subcursors
 	if (!(cursor_slice(&builder->mem, &builder->note_cur, half) &&
 	      cursor_slice(&builder->mem, &builder->strings, half) &&
 	      cursor_slice(&builder->mem, &builder->str_indices, str_indices_size))) {
 		return 0;
 	}
 
 	memset(note, 0, sizeof(*note));
 	builder->note_cur.p += sizeof(*note);
 
 	note->strings = builder->strings.start - buf;
 	note->version = 1;
 
 	return 1;
 }
 
 
 
 static inline int ndb_json_parser_init(struct ndb_json_parser *p,
 				       const char *json, int json_len,
 				       unsigned char *buf, int bufsize)
 {
 	int half = bufsize / 2;
 
 	unsigned char *tok_start = buf + half;
 	unsigned char *tok_end = buf + bufsize;
 
 	p->toks = (jsmntok_t*)tok_start;
 	p->toks_end = (jsmntok_t*)tok_end;
 	p->num_tokens = 0;
 	p->json = json;
 	p->json_len = json_len;
 
 	// ndb_builder gets the first half of the buffer, and jsmn gets the
 	// second half. I like this way of alloating memory (without actually
 	// dynamically allocating memory). You get one big chunk upfront and
 	// then submodules can recursively subdivide it. Maybe you could do
 	// something even more clever like golden-ratio style subdivision where
 	// the more important stuff gets a larger chunk and then it spirals
 	// downward into smaller chunks. Thanks for coming to my TED talk.
 
 	if (!ndb_builder_init(&p->builder, buf, half))
 		return 0;
 
 	jsmn_init(&p->json_parser);
 
 	return 1;
 }
 
 static inline int ndb_json_parser_parse(struct ndb_json_parser *p,
 					struct ndb_id_cb *cb)
 {
 	jsmntok_t *tok;
 	int cap = ((unsigned char *)p->toks_end - (unsigned char*)p->toks)/sizeof(*p->toks);
 	int res =
 		jsmn_parse(&p->json_parser, p->json, p->json_len, p->toks, cap, cb != NULL);
 
 	// got an ID!
 	if (res == -42) {
 		tok = &p->toks[p->json_parser.toknext-1];
 
 		switch (cb->fn(cb->data, p->json + tok->start)) {
 		case NDB_IDRES_CONT:
 			res = jsmn_parse(&p->json_parser, p->json, p->json_len,
 					 p->toks, cap, 0);
 			break;
 		case NDB_IDRES_STOP:
 			return -42;
 		}
 	} else if (res == 0) {
 		return 0;
 	}
 
 	p->num_tokens = res;
 	p->i = 0;
 
 	return 1;
 }
 
 static inline int toksize(jsmntok_t *tok)
 {
 	return tok->end - tok->start;
 }
 
 
 
 static int cursor_push_unescaped_char(struct cursor *cur, char c1, char c2)
 {
 	switch (c2) {
 	case 't':  return cursor_push_byte(cur, '\t');
 	case 'n':  return cursor_push_byte(cur, '\n');
 	case 'r':  return cursor_push_byte(cur, '\r');
 	case 'b':  return cursor_push_byte(cur, '\b');
 	case 'f':  return cursor_push_byte(cur, '\f');
 	case '\\': return cursor_push_byte(cur, '\\');
 	case '/':  return cursor_push_byte(cur, '/');
 	case '"':  return cursor_push_byte(cur, '"');
 	case 'u':
 		// these aren't handled yet
 		return 0;
 	default:
 		return cursor_push_byte(cur, c1) && cursor_push_byte(cur, c2);
 	}
 }
 
 static int cursor_push_escaped_char(struct cursor *cur, char c)
 {
         switch (c) {
         case '"':  return cursor_push_str(cur, "\\\"");
         case '\\': return cursor_push_str(cur, "\\\\");
         case '\b': return cursor_push_str(cur, "\\b");
         case '\f': return cursor_push_str(cur, "\\f");
         case '\n': return cursor_push_str(cur, "\\n");
         case '\r': return cursor_push_str(cur, "\\r");
         case '\t': return cursor_push_str(cur, "\\t");
         // TODO: \u hex hex hex hex
         }
         return cursor_push_byte(cur, c);
 }
 
 static int cursor_push_hex_str(struct cursor *cur, unsigned char *buf, int len)
 {
 	int i;
 
 	if (len % 2 != 0)
 		return 0;
 
         if (!cursor_push_byte(cur, '"'))
                 return 0;
 
 	for (i = 0; i < len; i++) {
 		unsigned int c = ((const unsigned char *)buf)[i];
 		if (!cursor_push_byte(cur, hexchar(c >> 4)))
 			return 0;
 		if (!cursor_push_byte(cur, hexchar(c & 0xF)))
 			return 0;
 	}
 
         if (!cursor_push_byte(cur, '"'))
                 return 0;
 
 	return 1;
 }
 
 static int cursor_push_jsonstr(struct cursor *cur, const char *str)
 {
 	int i;
         int len;
 
 	len = strlen(str);
 
         if (!cursor_push_byte(cur, '"'))
                 return 0;
 
         for (i = 0; i < len; i++) {
                 if (!cursor_push_escaped_char(cur, str[i]))
                         return 0;
         }
 
         if (!cursor_push_byte(cur, '"'))
                 return 0;
 
         return 1;
 }
 
 
 static inline int cursor_push_json_tag_str(struct cursor *cur, struct ndb_str str)
 {
 	if (str.flag == NDB_PACKED_ID)
 		return cursor_push_hex_str(cur, str.id, 32);
 
 	return cursor_push_jsonstr(cur, str.str);
 }
 
 static int cursor_push_json_tag(struct cursor *cur, struct ndb_note *note,
 				struct ndb_tag *tag)
 {
         int i;
 
         if (!cursor_push_byte(cur, '['))
                 return 0;
 
         for (i = 0; i < tag->count; i++) {
                 if (!cursor_push_json_tag_str(cur, ndb_tag_str(note, tag, i)))
                         return 0;
                 if (i != tag->count-1 && !cursor_push_byte(cur, ','))
 			return 0;
         }
 
         return cursor_push_byte(cur, ']');
 }
 
 static int cursor_push_json_tags(struct cursor *cur, struct ndb_note *note)
 {
 	int i;
 	struct ndb_iterator iter, *it = &iter;
 	ndb_tags_iterate_start(note, it);
 
         if (!cursor_push_byte(cur, '['))
                 return 0;
 
 	i = 0;
 	while (ndb_tags_iterate_next(it)) {
 		if (!cursor_push_json_tag(cur, note, it->tag))
 			return 0;
                 if (i != note->tags.count-1 && !cursor_push_str(cur, ","))
 			return 0;
 		i++;
 	}
 
         if (!cursor_push_byte(cur, ']'))
                 return 0;
 
 	return 1;
 }
 
 static int ndb_event_commitment(struct ndb_note *ev, unsigned char *buf, int buflen)
 {
 	char timebuf[16] = {0};
 	char kindbuf[16] = {0};
 	char pubkey[65];
 	struct cursor cur;
 	int ok;
 
 	if (!hex_encode(ev->pubkey, sizeof(ev->pubkey), pubkey))
 		return 0;
 
 	make_cursor(buf, buf + buflen, &cur);
 
 	// TODO: update in 2106 ...
 	snprintf(timebuf, sizeof(timebuf), "%d", (uint32_t)ev->created_at);
 	snprintf(kindbuf, sizeof(kindbuf), "%d", ev->kind);
 
 	ok =
 		cursor_push_str(&cur, "[0,\"") &&
 		cursor_push_str(&cur, pubkey) &&
 		cursor_push_str(&cur, "\",") &&
 		cursor_push_str(&cur, timebuf) &&
 		cursor_push_str(&cur, ",") &&
 		cursor_push_str(&cur, kindbuf) &&
 		cursor_push_str(&cur, ",") &&
 		cursor_push_json_tags(&cur, ev) &&
 		cursor_push_str(&cur, ",") &&
 		cursor_push_jsonstr(&cur, ndb_note_str(ev, &ev->content).str) &&
 		cursor_push_str(&cur, "]");
 
 	if (!ok)
 		return 0;
 
 	return cur.p - cur.start;
 }
 
 static int cursor_push_hex(struct cursor *c, unsigned char *bytes, int len)
 {
 	int i;
 	unsigned char chr;
 	if (c->p + (len * 2) >= c->end)
 		return 0;
 
 	for (i = 0; i < len; i++) {
 		chr = bytes[i];
 
 		*(c->p++) = hexchar(chr >> 4);
 		*(c->p++) = hexchar(chr & 0xF);
 	}
 
 	return 1;
 }
 
 static int cursor_push_int_str(struct cursor *c, uint64_t num)
 {
 	char timebuf[16] = {0};
 	snprintf(timebuf, sizeof(timebuf), "%" PRIu64, num);
 	return cursor_push_str(c, timebuf);
 }
 
 int ndb_note_json(struct ndb_note *note, char *buf, int buflen)
 {
 	struct cursor cur, *c = &cur;
 
 	make_cursor((unsigned char *)buf, (unsigned char*)buf + buflen, &cur);
 
 	int ok = cursor_push_str(c, "{\"id\":\"") &&
 	       cursor_push_hex(c, ndb_note_id(note), 32) &&
 	       cursor_push_str(c, "\",\"pubkey\":\"") &&
 	       cursor_push_hex(c, ndb_note_pubkey(note), 32) &&
 	       cursor_push_str(c, "\",\"created_at\":") &&
 	       cursor_push_int_str(c, ndb_note_created_at(note)) &&
 	       cursor_push_str(c, ",\"kind\":") &&
 	       cursor_push_int_str(c, ndb_note_kind(note)) &&
 	       cursor_push_str(c, ",\"tags\":") &&
 	       cursor_push_json_tags(c, note) &&
 	       cursor_push_str(c, ",\"content\":") &&
 	       cursor_push_jsonstr(c, ndb_note_content(note)) &&
 	       cursor_push_str(c, ",\"sig\":\"") &&
 	       cursor_push_hex(c, ndb_note_sig(note), 64) &&
 	       cursor_push_c_str(c, "\"}");
 
 	if (!ok) {
 		return 0;
 	}
 
 	return cur.p - cur.start;
 }
 
 static int cursor_push_json_elem_array(struct cursor *cur,
 				       const struct ndb_filter *filter,
 				       struct ndb_filter_elements *elems)
 {
 	int i;
 	unsigned char *id;
 	const char *str;
 	uint64_t val;
 
 	if (!cursor_push_byte(cur, '['))
 		return 0;
 
 	for (i = 0; i < elems->count; i++) {
 
 		switch (elems->field.elem_type)  {
 		case NDB_ELEMENT_STRING:
 			str = ndb_filter_get_string_element(filter, elems, i);
 			if (!cursor_push_jsonstr(cur, str))
 				return 0;
 			break;
 		case NDB_ELEMENT_ID:
 			id = ndb_filter_get_id_element(filter, elems, i);
 			if (!cursor_push_hex_str(cur, id, 32))
 				return 0;
 			break;
 		case NDB_ELEMENT_INT:
 			val = ndb_filter_get_int_element(elems, i);
 			if (!cursor_push_int_str(cur, val))
 				return 0;
 			break;
 		case NDB_ELEMENT_UNKNOWN:
 			ndb_debug("unknown element in cursor_push_json_elem_array");
 			return 0;
 		}
 
 		if (i != elems->count-1) {
 			if (!cursor_push_byte(cur, ','))
 				return 0;
 		}
 	}
 
 	if (!cursor_push_str(cur, "]"))
 		return 0;
 
 	return 1;
 }
 
 int ndb_filter_json(const struct ndb_filter *filter, char *buf, int buflen)
 {
 	const char *str;
 	struct cursor cur, *c = &cur;
 	struct ndb_filter_elements *elems;
 	int i;
 
 	if (!filter->finalized) {
 		ndb_debug("filter not finalized in ndb_filter_json\n");
 		return 0;
 	}
 
 	make_cursor((unsigned char *)buf, (unsigned char*)buf + buflen, c);
 
 	if (!cursor_push_str(c, "{"))
 		return 0;
 
 	for (i = 0; i < filter->num_elements; i++) {
 		elems = ndb_filter_get_elements(filter, i);
 		switch (elems->field.type) {
 		case NDB_FILTER_IDS:
 			if (!cursor_push_str(c, "\"ids\":"))
 				return 0;
 			if (!cursor_push_json_elem_array(c, filter, elems))
 				return 0;
 			break;
 		case NDB_FILTER_SEARCH:
 			if (!cursor_push_str(c, "\"search\":"))
 				return 0;
 			if (!(str = ndb_filter_get_string_element(filter, elems, 0)))
 				return 0;
 			if (!cursor_push_jsonstr(c, str))
 				return 0;
 			break;
 		case NDB_FILTER_AUTHORS:
 			if (!cursor_push_str(c, "\"authors\":"))
 				return 0;
 			if (!cursor_push_json_elem_array(c, filter, elems))
 				return 0;
 			break;
 		case NDB_FILTER_KINDS:
 			if (!cursor_push_str(c, "\"kinds\":"))
 				return 0;
 			if (!cursor_push_json_elem_array(c, filter, elems))
 				return 0;
 			break;
 		case NDB_FILTER_TAGS:
 			if (!cursor_push_str(c, "\"#"))
 				return 0;
 			if (!cursor_push_byte(c, elems->field.tag))
 				return 0;
 			if (!cursor_push_str(c, "\":"))
 				return 0;
 			if (!cursor_push_json_elem_array(c, filter, elems))
 				return 0;
 			break;
 		case NDB_FILTER_SINCE:
 			if (!cursor_push_str(c, "\"since\":"))
 				return 0;
 			if (!cursor_push_int_str(c, ndb_filter_get_int_element(elems, 0)))
 				return 0;
 			break;
 		case NDB_FILTER_UNTIL:
 			if (!cursor_push_str(c, "\"until\":"))
 				return 0;
 			if (!cursor_push_int_str(c, ndb_filter_get_int_element(elems, 0)))
 				return 0;
 			break;
 		case NDB_FILTER_LIMIT:
 			if (!cursor_push_str(c, "\"limit\":"))
 				return 0;
 			if (!cursor_push_int_str(c, ndb_filter_get_int_element(elems, 0)))
 				return 0;
 			break;
 		}
 
 		if (i != filter->num_elements-1) {
 			if (!cursor_push_byte(c, ',')) {
 				return 0;
 			}
 		}
 
 	}
 
 	if (!cursor_push_c_str(c, "}"))
 		return 0;
 
 	return cur.p - cur.start;
 }
 
 int ndb_calculate_id(struct ndb_note *note, unsigned char *buf, int buflen) {
 	int len;
 
 	if (!(len = ndb_event_commitment(note, buf, buflen)))
 		return 0;
 
 	//fprintf(stderr, "%.*s\n", len, buf);
 
 	sha256((struct sha256*)note->id, buf, len);
 
 	return 1;
 }
 
 int ndb_sign_id(struct ndb_keypair *keypair, unsigned char id[32],
 		unsigned char sig[64])
 {
 	unsigned char aux[32];
 	secp256k1_keypair *pair = (secp256k1_keypair*) keypair->pair;
 
 	if (!fill_random(aux, sizeof(aux)))
 		return 0;
 
 	secp256k1_context *ctx =
 		secp256k1_context_create(SECP256K1_CONTEXT_NONE);
 
 	return secp256k1_schnorrsig_sign32(ctx, sig, id, pair, aux);
 }
 
 int ndb_create_keypair(struct ndb_keypair *kp)
 {
 	secp256k1_keypair *keypair = (secp256k1_keypair*)kp->pair;
 	secp256k1_xonly_pubkey pubkey;
 
 	secp256k1_context *ctx =
 		secp256k1_context_create(SECP256K1_CONTEXT_NONE);;
 
 	/* Try to create a keypair with a valid context, it should only
 	 * fail if the secret key is zero or out of range. */
 	if (!secp256k1_keypair_create(ctx, keypair, kp->secret))
 		return 0;
 
 	if (!secp256k1_keypair_xonly_pub(ctx, &pubkey, NULL, keypair))
 		return 0;
 
 	/* Serialize the public key. Should always return 1 for a valid public key. */
 	return secp256k1_xonly_pubkey_serialize(ctx, kp->pubkey, &pubkey);
 }
 
 int ndb_decode_key(const char *secstr, struct ndb_keypair *keypair)
 {
 	if (!hex_decode(secstr, strlen(secstr), keypair->secret, 32)) {
 		fprintf(stderr, "could not hex decode secret key\n");
 		return 0;
 	}
 
 	return ndb_create_keypair(keypair);
 }
 
 int ndb_builder_finalize(struct ndb_builder *builder, struct ndb_note **note,
 			 struct ndb_keypair *keypair)
 {
 	int strings_len = builder->strings.p - builder->strings.start;
 	unsigned char *note_end = builder->note_cur.p + strings_len;
 	int total_size = note_end - builder->note_cur.start;
 
 	// move the strings buffer next to the end of our ndb_note
 	memmove(builder->note_cur.p, builder->strings.start, strings_len);
 
 	// set the strings location
 	builder->note->strings = builder->note_cur.p - builder->note_cur.start;
 
 	// record the total size
 	//builder->note->size = total_size;
 
 	*note = builder->note;
 
 	// generate id and sign if we're building this manually
 	if (keypair) {
 		// use the remaining memory for building our id buffer
 		unsigned char *end   = builder->mem.end;
 		unsigned char *start = (unsigned char*)(*note) + total_size;
 
 		ndb_builder_set_pubkey(builder, keypair->pubkey);
 
 		if (!ndb_calculate_id(builder->note, start, end - start))
 			return 0;
 
 		if (!ndb_sign_id(keypair, (*note)->id, (*note)->sig))
 			return 0;
 	}
 
 	// make sure we're aligned as a whole
 	total_size = (total_size + 7) & ~7;
 	assert((total_size % 8) == 0);
 	return total_size;
 }
 
 struct ndb_note * ndb_builder_note(struct ndb_builder *builder)
 {
 	return builder->note;
 }
 
 static union ndb_packed_str ndb_offset_str(uint32_t offset)
 {
 	// ensure accidents like -1 don't corrupt our packed_str
 	union ndb_packed_str str;
 	// most significant byte is reserved for ndb_packtype
 	str.offset = offset & 0xFFFFFF;
 	return str;
 }
 
 
 /// find an existing string via str_indices. these indices only exist in the
 /// builder phase just for this purpose.
 static inline int ndb_builder_find_str(struct ndb_builder *builder,
 				       const char *str, int len,
 				       union ndb_packed_str *pstr)
 {
 	// find existing matching string to avoid duplicate strings
 	int indices = cursor_count(&builder->str_indices, sizeof(uint32_t));
 	for (int i = 0; i < indices; i++) {
 		uint32_t index = ((uint32_t*)builder->str_indices.start)[i];
 		const char *some_str = (const char*)builder->strings.start + index;
 
 		if (!memcmp(some_str, str, len) && some_str[len] == '\0') {
 			// found an existing matching str, use that index
 			*pstr = ndb_offset_str(index);
 			return 1;
 		}
 	}
 
 	return 0;
 }
 
 static int ndb_builder_push_str(struct ndb_builder *builder, const char *str,
 				int len, union ndb_packed_str *pstr)
 {
 	uint32_t loc;
 
 	// no string found, push a new one
 	loc = builder->strings.p - builder->strings.start;
 	if (!(cursor_push(&builder->strings, (unsigned char*)str, len) &&
 	      cursor_push_byte(&builder->strings, '\0'))) {
 		return 0;
 	}
 
 	*pstr = ndb_offset_str(loc);
 
 	// record in builder indices. ignore return value, if we can't cache it
 	// then whatever
 	cursor_push_u32(&builder->str_indices, loc);
 
 	return 1;
 }
 
 static int ndb_builder_push_packed_id(struct ndb_builder *builder,
 				      unsigned char *id,
 				      union ndb_packed_str *pstr)
 {
 	// Don't both find id duplicates. very rarely are they duplicated
 	// and it slows things down quite a bit. If we really care about this
 	// We can switch to a hash table.
 	//if (ndb_builder_find_str(builder, (const char*)id, 32, pstr)) {
 	//	pstr->packed.flag = NDB_PACKED_ID;
 	//	return 1;
 	//}
 
 	if (ndb_builder_push_str(builder, (const char*)id, 32, pstr)) {
 		pstr->packed.flag = NDB_PACKED_ID;
 		return 1;
 	}
 
 	return 0;
 }
 
 union ndb_packed_str ndb_chars_to_packed_str(char c1, char c2)
 {
 	union ndb_packed_str str;
 	str.packed.flag = NDB_PACKED_STR;
 	str.packed.str[0] = c1;
 	str.packed.str[1] = c2;
 	str.packed.str[2] = '\0';
 	return str;
 }
 
 static union ndb_packed_str ndb_char_to_packed_str(char c)
 {
 	union ndb_packed_str str;
 	str.packed.flag = NDB_PACKED_STR;
 	str.packed.str[0] = c;
 	str.packed.str[1] = '\0';
 	return str;
 }
 
 
 /// Check for small strings to pack
 static inline int ndb_builder_try_compact_str(struct ndb_builder *builder,
 					      const char *str, int len,
 					      union ndb_packed_str *pstr,
 					      int pack_ids)
 {
 	unsigned char id_buf[32];
 
 	if (len == 0) {
 		*pstr = ndb_char_to_packed_str(0);
 		return 1;
 	} else if (len == 1) {
 		*pstr = ndb_char_to_packed_str(str[0]);
 		return 1;
 	} else if (len == 2) {
 		*pstr = ndb_chars_to_packed_str(str[0], str[1]);
 		return 1;
 	} else if (pack_ids && len == 64 && hex_decode(str, 64, id_buf, 32)) {
 		return ndb_builder_push_packed_id(builder, id_buf, pstr);
 	}
 
 	return 0;
 }
 
 
 static int ndb_builder_push_unpacked_str(struct ndb_builder *builder,
 					 const char *str, int len,
 					 union ndb_packed_str *pstr)
 {
 	if (ndb_builder_find_str(builder, str, len, pstr))
 		return 1;
 
 	return ndb_builder_push_str(builder, str, len, pstr);
 }
 
 int ndb_builder_make_str(struct ndb_builder *builder, const char *str, int len,
 			 union ndb_packed_str *pstr, int pack_ids)
 {
 	if (ndb_builder_try_compact_str(builder, str, len, pstr, pack_ids))
 		return 1;
 
 	return ndb_builder_push_unpacked_str(builder, str, len, pstr);
 }
 
 int ndb_builder_set_content(struct ndb_builder *builder, const char *content,
 			    int len)
 {
 	int pack_ids = 0;
 	builder->note->content_length = len;
 	return ndb_builder_make_str(builder, content, len,
 				    &builder->note->content, pack_ids);
 }
 
 
 static inline int jsoneq(const char *json, jsmntok_t *tok, int tok_len,
 			 const char *s)
 {
 	if (tok->type == JSMN_STRING && (int)strlen(s) == tok_len &&
 	    memcmp(json + tok->start, s, tok_len) == 0) {
 		return 1;
 	}
 	return 0;
 }
 
 static int ndb_builder_finalize_tag(struct ndb_builder *builder,
 				    union ndb_packed_str offset)
 {
 	if (!cursor_push_u32(&builder->note_cur, offset.offset))
 		return 0;
 	builder->current_tag->count++;
 	return 1;
 }
 
 /// Unescape and push json strings
 static int ndb_builder_make_json_str(struct ndb_builder *builder,
 				     const char *str, int len,
 				     union ndb_packed_str *pstr,
 				     int *written, int pack_ids)
 {
 	// let's not care about de-duping these. we should just unescape
 	// in-place directly into the strings table.
 	if (written)
 		*written = len;
 
 	const char *p, *end, *start;
 	unsigned char *builder_start;
 
 	// always try compact strings first
 	if (ndb_builder_try_compact_str(builder, str, len, pstr, pack_ids))
 		return 1;
 
 	end = str + len;
 	start = str; // Initialize start to the beginning of the string
 
 	*pstr = ndb_offset_str(builder->strings.p - builder->strings.start);
 	builder_start = builder->strings.p;
 
 	for (p = str; p < end; p++) {
 		if (*p == '\\' && p+1 < end) {
 			// Push the chunk of unescaped characters before this escape sequence
 			if (start < p && !cursor_push(&builder->strings,
 						(unsigned char *)start,
 						p - start)) {
 				return 0;
 			}
 
 			if (!cursor_push_unescaped_char(&builder->strings, *p, *(p+1)))
 				return 0;
 
 			p++; // Skip the character following the backslash
 			start = p + 1; // Update the start pointer to the next character
 		}
 	}
 
 	// Handle the last chunk after the last escape sequence (or if there are no escape sequences at all)
 	if (start < p && !cursor_push(&builder->strings, (unsigned char *)start,
 				      p - start)) {
 		return 0;
 	}
 
 	if (written)
 		*written = builder->strings.p - builder_start;
 
 	// TODO: dedupe these!?
 	return cursor_push_byte(&builder->strings, '\0');
 }
 
 static int ndb_builder_push_json_tag(struct ndb_builder *builder,
 				     const char *str, int len)
 {
 	union ndb_packed_str pstr;
 	int pack_ids = 1;
 	if (!ndb_builder_make_json_str(builder, str, len, &pstr, NULL, pack_ids))
 		return 0;
 	return ndb_builder_finalize_tag(builder, pstr);
 }
 
 // Push a json array into an ndb tag ["p", "abcd..."] -> struct ndb_tag
 static int ndb_builder_tag_from_json_array(struct ndb_json_parser *p,
 					   jsmntok_t *array)
 {
 	jsmntok_t *str_tok;
 	const char *str;
 
 	if (array->size == 0)
 		return 0;
 
 	if (!ndb_builder_new_tag(&p->builder))
 		return 0;
 
 	for (int i = 0; i < array->size; i++) {
 		str_tok = &array[i+1];
 		str = p->json + str_tok->start;
 
 		if (!ndb_builder_push_json_tag(&p->builder, str,
 					       toksize(str_tok))) {
 			return 0;
 		}
 	}
 
 	return 1;
 }
 
 // Push json tags into ndb data
 //   [["t", "hashtag"], ["p", "abcde..."]] -> struct ndb_tags
 static inline int ndb_builder_process_json_tags(struct ndb_json_parser *p,
 						jsmntok_t *array)
 {
 	jsmntok_t *tag = array;
 
 	if (array->size == 0)
 		return 1;
 
 	for (int i = 0; i < array->size; i++) {
 		if (!ndb_builder_tag_from_json_array(p, &tag[i+1]))
 			return 0;
 		tag += tag[i+1].size;
 	}
 
 	return 1;
 }
 
 static int parse_unsigned_int(const char *start, int len, unsigned int *num)
 {
 	unsigned int number = 0;
 	const char *p = start, *end = start + len;
 	int digits = 0;
 
 	while (p < end) {
 		char c = *p;
 
 		if (c < '0' || c > '9')
 			break;
 
 		// Check for overflow
 		char digit = c - '0';
 		if (number > (UINT_MAX - digit) / 10)
 			return 0; // Overflow detected
 
 		number = number * 10 + digit;
 
 		p++;
 		digits++;
 	}
 
 	if (digits == 0)
 		return 0;
 
 	*num = number;
 	return 1;
 }
 
 int ndb_client_event_from_json(const char *json, int len, struct ndb_fce *fce,
 			       unsigned char *buf, int bufsize, struct ndb_id_cb *cb)
 {
 	jsmntok_t *tok = NULL;
 	int tok_len, res;
 	struct ndb_json_parser parser;
 	struct ndb_event *ev = &fce->event;
 
 	ndb_json_parser_init(&parser, json, len, buf, bufsize);
 
 	if ((res = ndb_json_parser_parse(&parser, cb)) < 0)
 		return res;
 
 	if (parser.toks[0].type == JSMN_OBJECT) {
 		ndb_debug("got raw json in client_event_from_json\n");
 		fce->evtype = NDB_FCE_EVENT;
 		return ndb_parse_json_note(&parser, &ev->note);
 	}
 
 	if (parser.num_tokens <= 3 || parser.toks[0].type != JSMN_ARRAY)
 		return 0;
 
 	parser.i = 1;
 	tok = &parser.toks[parser.i++];
 	tok_len = toksize(tok);
 	if (tok->type != JSMN_STRING)
 		return 0;
 
 	if (tok_len == 5 && !memcmp("EVENT", json + tok->start, 5)) {
 		fce->evtype = NDB_FCE_EVENT;
 		return ndb_parse_json_note(&parser, &ev->note);
 	}
 
 	return 0;
 }
 
 
 int ndb_ws_event_from_json(const char *json, int len, struct ndb_tce *tce,
 			   unsigned char *buf, int bufsize,
 			   struct ndb_id_cb *cb)
 {
 	jsmntok_t *tok = NULL;
 	int tok_len, res;
 	struct ndb_json_parser parser;
 	struct ndb_event *ev = &tce->event;
 
 	tce->subid_len = 0;
 	tce->subid = "";
 
 	ndb_json_parser_init(&parser, json, len, buf, bufsize);
 
 	if ((res = ndb_json_parser_parse(&parser, cb)) < 0)
 		return res;
 
 	if (parser.toks[0].type == JSMN_OBJECT) {
 		ndb_debug("got raw json in ws_event_from_json\n");
 		tce->evtype = NDB_TCE_EVENT;
 		return ndb_parse_json_note(&parser, &ev->note);
 	}
 
 	if (parser.num_tokens < 3 || parser.toks[0].type != JSMN_ARRAY)
 		return 0;
 
 	parser.i = 1;
 	tok = &parser.toks[parser.i++];
 	tok_len = toksize(tok);
 	if (tok->type != JSMN_STRING)
 		return 0;
 
 	if (tok_len == 5 && !memcmp("EVENT", json + tok->start, 5)) {
 		tce->evtype = NDB_TCE_EVENT;
 
 		tok = &parser.toks[parser.i++];
 		if (tok->type != JSMN_STRING)
 			return 0;
 
 		tce->subid = json + tok->start;
 		tce->subid_len = toksize(tok);
 
 		return ndb_parse_json_note(&parser, &ev->note);
 	} else if (tok_len == 4 && !memcmp("EOSE", json + tok->start, 4)) {
 		tce->evtype = NDB_TCE_EOSE;
 
 		tok = &parser.toks[parser.i++];
 		if (tok->type != JSMN_STRING)
 			return 0;
 
 		tce->subid = json + tok->start;
 		tce->subid_len = toksize(tok);
 		return 1;
 	} else if (tok_len == 2 && !memcmp("OK", json + tok->start, 2)) {
 		if (parser.num_tokens != 5)
 			return 0;
 
 		struct ndb_command_result *cr = &tce->command_result;
 
 		tce->evtype = NDB_TCE_OK;
 
 		tok = &parser.toks[parser.i++];
 		if (tok->type != JSMN_STRING)
 			return 0;
 
 		tce->subid = json + tok->start;
 		tce->subid_len = toksize(tok);
 
 		tok = &parser.toks[parser.i++];
 		if (tok->type != JSMN_PRIMITIVE || toksize(tok) == 0)
 			return 0;
 
 		cr->ok = (json + tok->start)[0] == 't';
 
 		tok = &parser.toks[parser.i++];
 		if (tok->type != JSMN_STRING)
 			return 0;
 
 		tce->command_result.msg = json + tok->start;
 		tce->command_result.msglen = toksize(tok);
 
 		return 1;
 	} else if (tok_len == 4 && !memcmp("AUTH", json + tok->start, 4)) {
 		tce->evtype = NDB_TCE_AUTH;
 
 		tok = &parser.toks[parser.i++];
 		if (tok->type != JSMN_STRING)
 			return 0;
 
 		tce->subid = json + tok->start;
 		tce->subid_len = toksize(tok);
 
 		return 1;
 	}
 
 	return 0;
 }
 
 static enum ndb_filter_fieldtype
 ndb_filter_parse_field(const char *tok, int len, char *tagchar)
 {
 	*tagchar = 0;
 
 	if (len == 0)
 		return 0;
 
 	if (len == 7 && !strncmp(tok, "authors", 7)) {
 		return NDB_FILTER_AUTHORS;
 	} else if (len == 3 && !strncmp(tok, "ids", 3)) {
 		return NDB_FILTER_IDS;
 	} else if (len == 5 && !strncmp(tok, "kinds", 5)) {
 		return NDB_FILTER_KINDS;
 	} else if (len == 2 && tok[0] == '#') {
 		*tagchar = tok[1];
 		return NDB_FILTER_TAGS;
 	} else if (len == 5 && !strncmp(tok, "since", 5)) {
 		return NDB_FILTER_SINCE;
 	} else if (len == 5 && !strncmp(tok, "until", 5)) {
 		return NDB_FILTER_UNTIL;
 	} else if (len == 5 && !strncmp(tok, "limit", 5)) {
 		return NDB_FILTER_LIMIT;
 	} else if (len == 6 && !strncmp(tok, "search", 6)) {
 		return NDB_FILTER_SEARCH;
 	}
 
 	return 0;
 }
 
 static int ndb_filter_parse_json_ids(struct ndb_json_parser *parser,
 				     struct ndb_filter *filter)
 {
 	jsmntok_t *tok;
 	const char *start;
 	unsigned char hexbuf[32];
 	int tok_len, i, size;
 
 	tok = &parser->toks[parser->i++];
 
 	if (tok->type != JSMN_ARRAY) {
 		ndb_debug("parse_json_ids: not an array\n");
 		return 0;
 	}
 
 	size = tok->size;
 
 	for (i = 0; i < size; parser->i++, i++) {
 		tok = &parser->toks[parser->i];
 		start = parser->json + tok->start;
 		tok_len = toksize(tok);
 
 		if (tok->type != JSMN_STRING) {
 			ndb_debug("parse_json_ids: not a string '%d'\n", tok->type);
 			return 0;
 		}
 
 		if (tok_len != 64) {
 			ndb_debug("parse_json_ids: not len 64: '%.*s'\n", tok_len, start);
 			return 0;
 		}
 
 		// id
 		if (!hex_decode(start, tok_len, hexbuf, sizeof(hexbuf))) {
 			ndb_debug("parse_json_ids: hex decode failed\n");
 			return 0;
 		}
 
 		ndb_debug("adding id elem\n");
 		if (!ndb_filter_add_id_element(filter, hexbuf)) {
 			ndb_debug("parse_json_ids: failed to add id element\n");
 			return 0;
 		}
 	}
 
 	parser->i--;
 	return 1;
 }
 
 static int ndb_filter_parse_json_elems(struct ndb_json_parser *parser,
 				       struct ndb_filter *filter)
 {
 	jsmntok_t *tok;
 	const char *start;
 	int tok_len;
 	unsigned char hexbuf[32];
 	enum ndb_generic_element_type typ;
 	tok = NULL;
 	int i, size;
 
 	tok = &parser->toks[parser->i++];
 
 	if (tok->type != JSMN_ARRAY)
 		return 0;
 
 	size = tok->size;
 
 	for (i = 0; i < size; i++, parser->i++) {
 		tok = &parser->toks[parser->i];
 		start = parser->json + tok->start;
 		tok_len = toksize(tok);
 
 		if (tok->type != JSMN_STRING)
 			return 0;
 
 		if (i == 0) {
 			if (tok_len == 64 && hex_decode(start, 64, hexbuf, sizeof(hexbuf))) {
 				typ = NDB_ELEMENT_ID;
 				if (!ndb_filter_add_id_element(filter, hexbuf)) {
 					ndb_debug("failed to push id elem\n");
 					return 0;
 				}
 			} else {
 				typ = NDB_ELEMENT_STRING;
 				if (!ndb_filter_add_str_element_len(filter, start, tok_len))
 					return 0;
 			}
 		} else if (typ == NDB_ELEMENT_ID) {
 			if (!hex_decode(start, 64, hexbuf, sizeof(hexbuf)))
 				return 0;
 			if (!ndb_filter_add_id_element(filter, hexbuf))
 				return 0;
 		} else if (typ == NDB_ELEMENT_STRING) {
 			if (!ndb_filter_add_str_element_len(filter, start, tok_len))
 				return 0;
 		} else {
 			// ???
 			return 0;
 		}
 	}
 
 	parser->i--;
 	return 1;
 }
 
 static int ndb_filter_parse_json_str(struct ndb_json_parser *parser,
 				     struct ndb_filter *filter)
 {
 	jsmntok_t *tok;
 	const char *start;
 	int tok_len;
 
 	tok = &parser->toks[parser->i];
 	start = parser->json + tok->start;
 	tok_len = toksize(tok);
 
 	if (tok->type != JSMN_STRING)
 		return 0;
 
 	if (!ndb_filter_add_str_element_len(filter, start, tok_len))
 		return 0;
 
 	ndb_debug("added str elem '%.*s'\n", tok_len, start);
 
 	return 1;
 }
 
 static int ndb_filter_parse_json_int(struct ndb_json_parser *parser,
 				     struct ndb_filter *filter)
 {
 	jsmntok_t *tok;
 	const char *start;
 	int tok_len;
 	unsigned int value;
 
 	tok = &parser->toks[parser->i];
 	start = parser->json + tok->start;
 	tok_len = toksize(tok);
 
 	if (tok->type != JSMN_PRIMITIVE)
 		return 0;
 
 	if (!parse_unsigned_int(start, tok_len, &value))
 		return 0;
 
 	if (!ndb_filter_add_int_element(filter, (uint64_t)value))
 		return 0;
 
 	ndb_debug("added int elem %d\n", value);
 
 	return 1;
 }
 
 
 static int ndb_filter_parse_json_ints(struct ndb_json_parser *parser,
 				      struct ndb_filter *filter)
 {
 	jsmntok_t *tok;
 	int size, i;
 
 	tok = &parser->toks[parser->i++];
 
 	if (tok->type != JSMN_ARRAY)
 		return 0;
 
 	size = tok->size;
 
 	for (i = 0; i < size; parser->i++, i++) {
 		if (!ndb_filter_parse_json_int(parser, filter))
 			return 0;
 	}
 
 	parser->i--;
 	return 1;
 }
 
 
 static int ndb_filter_parse_json(struct ndb_json_parser *parser,
 				 struct ndb_filter *filter)
 {
 	jsmntok_t *tok = NULL;
 	const char *json = parser->json;
 	const char *start;
 	char tag;
 	int tok_len;
 	enum ndb_filter_fieldtype field;
 
 	if (parser->toks[parser->i++].type != JSMN_OBJECT)
 		return 0;
 
 	for (; parser->i < parser->num_tokens; parser->i++) {
 		tok = &parser->toks[parser->i++];
 		start = json + tok->start;
 		tok_len = toksize(tok);
 
 		if (!(field = ndb_filter_parse_field(start, tok_len, &tag))) {
 			ndb_debug("failed field '%.*s'\n", tok_len, start);
 			continue;
 		}
 
 		if (tag) {
 			ndb_debug("starting tag field '%c'\n", tag);
 			if (!ndb_filter_start_tag_field(filter, tag)) {
 				ndb_debug("failed to start tag field '%c'\n", tag);
 				return 0;
 			}
 		} else if (!ndb_filter_start_field(filter, field)) {
 			ndb_debug("field already started\n");
 			return 0;
 		}
 
 		// we parsed a top-level field
 		switch(field) {
 		case NDB_FILTER_AUTHORS:
 		case NDB_FILTER_IDS:
 			if (!ndb_filter_parse_json_ids(parser, filter)) {
 				ndb_debug("failed to parse filter ids/authors\n");
 				return 0;
 			}
 			break;
 		case NDB_FILTER_SEARCH:
 			if (!ndb_filter_parse_json_str(parser, filter)) {
 				ndb_debug("failed to parse filter search str\n");
 				return 0;
 			}
 			break;
 		case NDB_FILTER_SINCE:
 		case NDB_FILTER_UNTIL:
 		case NDB_FILTER_LIMIT:
 			if (!ndb_filter_parse_json_int(parser, filter)) {
 				ndb_debug("failed to parse filter since/until/limit\n");
 				return 0;
 			}
 			break;
 		case NDB_FILTER_KINDS:
 			if (!ndb_filter_parse_json_ints(parser, filter)) {
 				ndb_debug("failed to parse filter kinds\n");
 				return 0;
 			}
 			break;
 		case NDB_FILTER_TAGS:
 			if (!ndb_filter_parse_json_elems(parser, filter)) {
 				ndb_debug("failed to parse filter tags\n");
 				return 0;
 			}
 			break;
 		}
 
 		ndb_filter_end_field(filter);
 	}
 
 	return ndb_filter_end(filter);
 }
 
 int ndb_parse_json_note(struct ndb_json_parser *parser, struct ndb_note **note)
 {
 	jsmntok_t *tok = NULL;
 	unsigned char hexbuf[64];
 	const char *json = parser->json;
 	const char *start;
 	int i, tok_len, parsed;
 
 	parsed = 0;
 
 	if (parser->toks[parser->i].type != JSMN_OBJECT)
 		return 0;
 
 	// TODO: build id buffer and verify at end
 
 	for (i = parser->i + 1; i < parser->num_tokens; i++) {
 		tok = &parser->toks[i];
 		start = json + tok->start;
 		tok_len = toksize(tok);
 
 		//printf("toplevel %.*s %d\n", tok_len, json + tok->start, tok->type);
 		if (tok_len == 0 || i + 1 >= parser->num_tokens)
 			continue;
 
 		if (start[0] == 'p' && jsoneq(json, tok, tok_len, "pubkey")) {
 			// pubkey
 			tok = &parser->toks[i+1];
 			hex_decode(json + tok->start, toksize(tok), hexbuf, sizeof(hexbuf));
 			parsed |= NDB_PARSED_PUBKEY;
 			ndb_builder_set_pubkey(&parser->builder, hexbuf);
 		} else if (tok_len == 2 && start[0] == 'i' && start[1] == 'd') {
 			// id
 			tok = &parser->toks[i+1];
 			hex_decode(json + tok->start, toksize(tok), hexbuf, sizeof(hexbuf));
 			parsed |= NDB_PARSED_ID;
 			ndb_builder_set_id(&parser->builder, hexbuf);
 		} else if (tok_len == 3 && start[0] == 's' && start[1] == 'i' && start[2] == 'g') {
 			// sig
 			tok = &parser->toks[i+1];
 			hex_decode(json + tok->start, toksize(tok), hexbuf, sizeof(hexbuf));
 			parsed |= NDB_PARSED_SIG;
 			ndb_builder_set_sig(&parser->builder, hexbuf);
 		} else if (start[0] == 'k' && jsoneq(json, tok, tok_len, "kind")) {
 			// kind
 			tok = &parser->toks[i+1];
 			start = json + tok->start;
 			if (tok->type != JSMN_PRIMITIVE || tok_len <= 0)
 				return 0;
 			if (!parse_unsigned_int(start, toksize(tok),
 						&parser->builder.note->kind))
 					return 0;
 			parsed |= NDB_PARSED_KIND;
 		} else if (start[0] == 'c') {
 			if (jsoneq(json, tok, tok_len, "created_at")) {
 				// created_at
 				tok = &parser->toks[i+1];
 				start = json + tok->start;
 				if (tok->type != JSMN_PRIMITIVE || tok_len <= 0)
 					return 0;
 				// TODO: update to int64 in 2106 ... xD
 				unsigned int bigi;
 				if (!parse_unsigned_int(start, toksize(tok), &bigi))
 					return 0;
 				parser->builder.note->created_at = bigi;
 				parsed |= NDB_PARSED_CREATED_AT;
 			} else if (jsoneq(json, tok, tok_len, "content")) {
 				// content
 				tok = &parser->toks[i+1];
 				union ndb_packed_str pstr;
 				tok_len = toksize(tok);
 				int written, pack_ids = 0;
 				if (!ndb_builder_make_json_str(&parser->builder,
 							json + tok->start,
 							tok_len, &pstr,
 							&written, pack_ids)) {
 					ndb_debug("ndb_builder_make_json_str failed\n");
 					return 0;
 				}
 				parser->builder.note->content_length = written;
 				parser->builder.note->content = pstr;
 				parsed |= NDB_PARSED_CONTENT;
 			}
 		} else if (start[0] == 't' && jsoneq(json, tok, tok_len, "tags")) {
 			tok = &parser->toks[i+1];
 			ndb_builder_process_json_tags(parser, tok);
 			i += tok->size;
 			parsed |= NDB_PARSED_TAGS;
 		}
 	}
 
 	//ndb_debug("parsed %d = %d, &->%d", parsed, NDB_PARSED_ALL, parsed & NDB_PARSED_ALL);
 	if (parsed != NDB_PARSED_ALL)
 		return 0;
 
 	return ndb_builder_finalize(&parser->builder, note, NULL);
 }
 
 int ndb_filter_from_json(const char *json, int len, struct ndb_filter *filter,
 			 unsigned char *buf, int bufsize)
 {
 	struct ndb_json_parser parser;
 	int res;
 
 	if (filter->finalized)
 		return 0;
 
 	ndb_json_parser_init(&parser, json, len, buf, bufsize);
 	if ((res = ndb_json_parser_parse(&parser, NULL)) < 0)
 		return res;
 
 	if (parser.num_tokens < 1)
 		return 0;
 
 	return ndb_filter_parse_json(&parser, filter);
 }
 
 int ndb_note_from_json(const char *json, int len, struct ndb_note **note,
 		       unsigned char *buf, int bufsize)
 {
 	struct ndb_json_parser parser;
 	int res;
 
 	ndb_json_parser_init(&parser, json, len, buf, bufsize);
 	if ((res = ndb_json_parser_parse(&parser, NULL)) < 0)
 		return res;
 
 	if (parser.num_tokens < 1)
 		return 0;
 
 	return ndb_parse_json_note(&parser, note);
 }
 
 void ndb_builder_set_pubkey(struct ndb_builder *builder, unsigned char *pubkey)
 {
 	memcpy(builder->note->pubkey, pubkey, 32);
 }
 
 void ndb_builder_set_id(struct ndb_builder *builder, unsigned char *id)
 {
 	memcpy(builder->note->id, id, 32);
 }
 
 void ndb_builder_set_sig(struct ndb_builder *builder, unsigned char *sig)
 {
 	memcpy(builder->note->sig, sig, 64);
 }
 
 void ndb_builder_set_kind(struct ndb_builder *builder, uint32_t kind)
 {
 	builder->note->kind = kind;
 }
 
 void ndb_builder_set_created_at(struct ndb_builder *builder, uint64_t created_at)
 {
 	builder->note->created_at = created_at;
 }
 
 int ndb_builder_new_tag(struct ndb_builder *builder)
 {
 	builder->note->tags.count++;
 	struct ndb_tag tag = {0};
 	builder->current_tag = (struct ndb_tag *)builder->note_cur.p;
 	return cursor_push_tag(&builder->note_cur, &tag);
 }
 
 void ndb_stat_counts_init(struct ndb_stat_counts *counts)
 {
 	counts->count = 0;
 	counts->key_size = 0;
 	counts->value_size = 0;
 }
 
 static void ndb_stat_init(struct ndb_stat *stat)
 {
 	// init stats
 	int i;
 
 	for (i = 0; i < NDB_CKIND_COUNT; i++) {
 		ndb_stat_counts_init(&stat->common_kinds[i]);
 	}
 
 	for (i = 0; i < NDB_DBS; i++) {
 		ndb_stat_counts_init(&stat->dbs[i]);
 	}
 
 	ndb_stat_counts_init(&stat->other_kinds);
 }
 
 int ndb_stat(struct ndb *ndb, struct ndb_stat *stat)
 {
 	int rc;
 	MDB_cursor *cur;
 	MDB_val k, v;
 	MDB_dbi db;
 	struct ndb_txn txn;
 	struct ndb_note *note;
 	int i;
 	enum ndb_common_kind common_kind;
 
 	// initialize to 0
 	ndb_stat_init(stat);
 
 	if (!ndb_begin_query(ndb, &txn)) {
 		fprintf(stderr, "ndb_stat failed at ndb_begin_query\n");
 		return 0;
 	}
 
 	// stat each dbi in the database
 	for (i = 0; i < NDB_DBS; i++)
 	{
 		db = ndb->lmdb.dbs[i];
 
 		if ((rc = mdb_cursor_open(txn.mdb_txn, db, &cur))) {
 			fprintf(stderr, "ndb_stat: mdb_cursor_open failed, error '%s'\n",
 					mdb_strerror(rc));
 			return 0;
 		}
 
 		// loop over every entry and count kv sizes
 		while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
 			// we gather more detailed per-kind stats if we're in
 			// the notes db
 			if (i == NDB_DB_NOTE) {
 				note = v.mv_data;
 				common_kind = ndb_kind_to_common_kind(note->kind);
 
 				// uncommon kind? just count them in bulk
 				if ((int)common_kind == -1) {
 					stat->other_kinds.count++;
 					stat->other_kinds.key_size += k.mv_size;
 					stat->other_kinds.value_size += v.mv_size;
 				} else {
 					stat->common_kinds[common_kind].count++;
 					stat->common_kinds[common_kind].key_size += k.mv_size;
 					stat->common_kinds[common_kind].value_size += v.mv_size;
 				}
 			}
 
 			stat->dbs[i].count++;
 			stat->dbs[i].key_size += k.mv_size;
 			stat->dbs[i].value_size += v.mv_size;
 		}
 
 		// close the cursor, they are per-dbi
 		mdb_cursor_close(cur);
 	}
 
 	ndb_end_query(&txn);
 
 	return 1;
 }
 
 /// Push an element to the current tag
 ///
 /// Basic idea is to call ndb_builder_new_tag
 int ndb_builder_push_tag_str(struct ndb_builder *builder,
 				    const char *str, int len)
 {
 	union ndb_packed_str pstr;
 	int pack_ids = 1;
 	if (!ndb_builder_make_str(builder, str, len, &pstr, pack_ids))
 		return 0;
 	return ndb_builder_finalize_tag(builder, pstr);
 }
 
 //
 // CONFIG
 //
 void ndb_default_config(struct ndb_config *config)
 {
 	int cores = get_cpu_cores();
 	config->mapsize = 1024UL * 1024UL * 1024UL * 32UL; // 32 GiB
 	config->ingester_threads = cores == -1 ? 4 : cores;
 	config->flags = 0;
 	config->ingest_filter = NULL;
 	config->filter_context = NULL;
 	config->sub_cb_ctx = NULL;
 	config->sub_cb = NULL;
 	config->writer_scratch_buffer_size = DEFAULT_WRITER_SCRATCH_SIZE;
 }
 
 void ndb_config_set_subscription_callback(struct ndb_config *config, ndb_sub_fn fn, void *context)
 {
 	config->sub_cb_ctx = context;
 	config->sub_cb = fn;
 }
 
 void ndb_config_set_writer_scratch_buffer_size(struct ndb_config *config, int scratch_size)
 {
 	config->writer_scratch_buffer_size = scratch_size;
 }
 
 void ndb_config_set_ingest_threads(struct ndb_config *config, int threads)
 {
 	config->ingester_threads = threads;
 }
 
 void ndb_config_set_flags(struct ndb_config *config, int flags)
 {
 	config->flags = flags;
 }
 
 void ndb_config_set_mapsize(struct ndb_config *config, size_t mapsize)
 {
 	config->mapsize = mapsize;
 }
 
 void ndb_config_set_ingest_filter(struct ndb_config *config,
 				  ndb_ingest_filter_fn fn, void *filter_ctx)
 {
 	config->ingest_filter = fn;
 	config->filter_context = filter_ctx;
 }
 
 int ndb_print_relay_kind_index(struct ndb_txn *txn)
 {
 	MDB_cursor *cur;
 	MDB_val k, v;
 	int i;
 
 	if (mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_RELAY_KIND], &cur))
 		return 0;
 
 	i = 1;
 	printf("relay\tkind\tcreated_at\tnote_id\n");
 	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
 		printf("%s\t", (const char *)(k.mv_data + 25));
 		printf("%" PRIu64 "\t", *(uint64_t*)(k.mv_data + 8));
 		printf("%" PRIu64 "\t", *(uint64_t*)(k.mv_data + 16));
 		printf("%" PRIu64 "\n", *(uint64_t*)(k.mv_data + 0));
 		i++;
 	}
 
 	return i;
 }
 
 int ndb_print_tag_index(struct ndb_txn *txn)
 {
 	MDB_cursor *cur;
 	MDB_val k, v;
 	int i;
 
 	if (mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_TAGS], &cur))
 		return 0;
 
 	i = 1;
 	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
 		printf("%d ", i);
 		print_tag_kv(txn, &k, &v);
 		i++;
 	}
 
 	return 1;
 }
 
 int ndb_print_kind_keys(struct ndb_txn *txn)
 {
 	MDB_cursor *cur;
 	MDB_val k, v;
 	int i;
 	struct ndb_u64_ts *tsid;
 
 	if (mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_KIND], &cur))
 		return 0;
 
 	i = 1;
 	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
 		tsid = k.mv_data;
 		printf("%d note_kind %" PRIu64 " %" PRIu64 "\n",
 			i, tsid->u64, tsid->timestamp);
 
 		i++;
 	}
 
 	return 1;
 }
 
 // used by ndb.c
 int ndb_print_search_keys(struct ndb_txn *txn)
 {
 	MDB_cursor *cur;
 	MDB_val k, v;
 	int i;
 	struct ndb_text_search_key search_key;
 
 	if (mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_TEXT], &cur))
 		return 0;
 
 	i = 1;
 	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
 		if (!ndb_unpack_text_search_key(k.mv_data, k.mv_size, &search_key)) {
 			fprintf(stderr, "error decoding key %d\n", i);
 			continue;
 		}
 
 		ndb_print_text_search_key(k.mv_size, &search_key);
 		printf("\n");
 
 		i++;
 	}
 
 	return 1;
 }
 
 struct ndb_tags *ndb_note_tags(struct ndb_note *note)
 {
 	return &note->tags;
 }
 
 struct ndb_str ndb_note_str(struct ndb_note *note, union ndb_packed_str *pstr)
 {
 	struct ndb_str str;
 	str.flag = pstr->packed.flag;
 
 	if (str.flag == NDB_PACKED_STR) {
 		str.str = pstr->packed.str;
 		return str;
 	}
 
 	str.str = ((const char *)note) + note->strings + (pstr->offset & 0xFFFFFF);
 	return str;
 }
 
 struct ndb_str ndb_tag_str(struct ndb_note *note, struct ndb_tag *tag, int ind)
 {
 	return ndb_note_str(note, &tag->strs[ind]);
 }
 
 int ndb_str_len(struct ndb_str *str)
 {
 	if (str->flag == NDB_PACKED_ID)
 		return 32;
 	return strlen(str->str);
 }
 
 struct ndb_str ndb_iter_tag_str(struct ndb_iterator *iter, int ind)
 {
 	return ndb_tag_str(iter->note, iter->tag, ind);
 }
 
 unsigned char * ndb_note_id(struct ndb_note *note)
 {
 	return note->id;
 }
 
 unsigned char * ndb_note_pubkey(struct ndb_note *note)
 {
 	return note->pubkey;
 }
 
 unsigned char * ndb_note_sig(struct ndb_note *note)
 {
 	return note->sig;
 }
 
 uint32_t ndb_note_created_at(struct ndb_note *note)
 {
 	return note->created_at;
 }
 
 uint32_t ndb_note_kind(struct ndb_note *note)
 {
 	return note->kind;
 }
 
 void _ndb_note_set_kind(struct ndb_note *note, uint32_t kind)
 {
 	note->kind = kind;
 }
 
 const char *ndb_note_content(struct ndb_note *note)
 {
 	return ndb_note_str(note, &note->content).str;
 }
 
 uint32_t ndb_note_content_length(struct ndb_note *note)
 {
 	return note->content_length;
 }
 
 struct ndb_note * ndb_note_from_bytes(unsigned char *bytes)
 {
 	struct ndb_note *note = (struct ndb_note *)bytes;
 	if (note->version != 1)
 		return 0;
 	return note;
 }
 
 int ndb_note_relay_iterate_start(struct ndb_txn *txn,
 				 struct ndb_note_relay_iterator *iter,
 				 uint64_t note_key)
 {
 	if (mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_RELAYS],
 			    (MDB_cursor**)&iter->mdb_cur)) {
 		return 0;
 	}
 
 	iter->txn = txn;
 	iter->cursor_op = MDB_SET_KEY;
 	iter->note_key = note_key;
 
 	return 1;
 }
 
 const char *ndb_note_relay_iterate_next(struct ndb_note_relay_iterator *iter)
 {
 	int rc;
 	MDB_val k, v;
 
 	if (iter->mdb_cur == NULL)
 		return NULL;
 
 	k.mv_data = &iter->note_key;
 	k.mv_size = sizeof(iter->note_key);
 
 	if ((rc = mdb_cursor_get((MDB_cursor *)iter->mdb_cur, &k, &v,
 				 (MDB_cursor_op)iter->cursor_op)))
 	{
 		//fprintf(stderr, "autoclosing %d '%s'\n", iter->cursor_op, mdb_strerror(rc));
 		// autoclose
 		ndb_note_relay_iterate_close(iter);
 		return NULL;
 	}
 
 	iter->cursor_op = MDB_NEXT_DUP;
 
 	return (const char*)v.mv_data;
 }
 
 void ndb_note_relay_iterate_close(struct ndb_note_relay_iterator *iter)
 {
 	if (!iter || iter->mdb_cur == NULL)
 		return;
 
 	mdb_cursor_close((MDB_cursor*)iter->mdb_cur);
 
 	iter->mdb_cur = NULL;
 }
 
 void ndb_tags_iterate_start(struct ndb_note *note, struct ndb_iterator *iter)
 {
 	iter->note = note;
 	iter->tag = NULL;
 	iter->index = -1;
 }
 
 // Helper function to get a pointer to the nth tag
 static struct ndb_tag *ndb_tags_tag(struct ndb_tags *tags, size_t index) {
     return (struct ndb_tag *)((uint8_t *)tags + sizeof(struct ndb_tags) + index * sizeof(struct ndb_tag));
 }
 
 int ndb_tags_iterate_next(struct ndb_iterator *iter)
 {
 	struct ndb_tags *tags;
 
 	if (iter->tag == NULL || iter->index == -1) {
 		iter->tag = ndb_tags_tag(&iter->note->tags, 0);
 		iter->index = 0;
 		return iter->note->tags.count != 0;
 	}
 
 	tags = &iter->note->tags;
 
 	if (++iter->index < tags->count) {
 		uint32_t tag_data_size = iter->tag->count * sizeof(iter->tag->strs[0]);
 		iter->tag = (struct ndb_tag *)(iter->tag->strs[0].bytes + tag_data_size);
 		return 1;
 	}
 
 	return 0;
 }
 
 uint16_t ndb_tags_count(struct ndb_tags *tags)
 {
 	return tags->count;
 }
 
 uint16_t ndb_tag_count(struct ndb_tag *tags)
 {
 	return tags->count;
 }
 
 enum ndb_common_kind ndb_kind_to_common_kind(int kind)
 {
 	switch (kind)
 	{
 		case 0:     return NDB_CKIND_PROFILE;
 		case 1:     return NDB_CKIND_TEXT;
 		case 3:     return NDB_CKIND_CONTACTS;
 		case 4:     return NDB_CKIND_DM;
 		case 5:     return NDB_CKIND_DELETE;
 		case 6:     return NDB_CKIND_REPOST;
 		case 7:     return NDB_CKIND_REACTION;
 		case 9735:  return NDB_CKIND_ZAP;
 		case 9734:  return NDB_CKIND_ZAP_REQUEST;
 		case 23194: return NDB_CKIND_NWC_REQUEST;
 		case 23195: return NDB_CKIND_NWC_RESPONSE;
 		case 27235: return NDB_CKIND_HTTP_AUTH;
 		case 30000: return NDB_CKIND_LIST;
 		case 30023: return NDB_CKIND_LONGFORM;
 		case 30315: return NDB_CKIND_STATUS;
 	}
 
 	return -1;
 }
 
 const char *ndb_kind_name(enum ndb_common_kind ck)
 {
 	switch (ck) {
 		case NDB_CKIND_PROFILE:      return "profile";
 		case NDB_CKIND_TEXT:         return "text";
 		case NDB_CKIND_CONTACTS:     return "contacts";
 		case NDB_CKIND_DM:           return "dm";
 		case NDB_CKIND_DELETE:       return "delete";
 		case NDB_CKIND_REPOST:       return "repost";
 		case NDB_CKIND_REACTION:     return "reaction";
 		case NDB_CKIND_ZAP:          return "zap";
 		case NDB_CKIND_ZAP_REQUEST:  return "zap_request";
 		case NDB_CKIND_NWC_REQUEST:  return "nwc_request";
 		case NDB_CKIND_NWC_RESPONSE: return "nwc_response";
 		case NDB_CKIND_HTTP_AUTH:    return "http_auth";
 		case NDB_CKIND_LIST:         return "list";
 		case NDB_CKIND_LONGFORM:     return "longform";
 		case NDB_CKIND_STATUS:       return "status";
 		case NDB_CKIND_COUNT:        return "unknown";
 	}
 
 	return "unknown";
 }
 
 const char *ndb_db_name(enum ndb_dbs db)
 {
 	switch (db) {
 		case NDB_DB_NOTE:
 			return "note";
 		case NDB_DB_META:
 			return "note_metadata";
 		case NDB_DB_PROFILE:
 			return "profile";
 		case NDB_DB_NOTE_ID:
 			return "note_index";
 		case NDB_DB_PROFILE_PK:
 			return "profile_pubkey_index";
 		case NDB_DB_NDB_META:
 			return "nostrdb_metadata";
 		case NDB_DB_PROFILE_SEARCH:
 			return "profile_search";
 		case NDB_DB_PROFILE_LAST_FETCH:
 			return "profile_last_fetch";
 		case NDB_DB_NOTE_KIND:
 			return "note_kind_index";
 		case NDB_DB_NOTE_TEXT:
 			return "note_fulltext";
 		case NDB_DB_NOTE_BLOCKS:
 			return "note_blocks";
 		case NDB_DB_NOTE_TAGS:
 			return "note_tags";
 		case NDB_DB_NOTE_PUBKEY:
 			return "note_pubkey_index";
 		case NDB_DB_NOTE_PUBKEY_KIND:
 			return "note_pubkey_kind_index";
 		case NDB_DB_NOTE_RELAY_KIND:
 			return "note_relay_kind_index";
 		case NDB_DB_NOTE_RELAYS:
 			return "note_relays";
 		case NDB_DBS:
 			return "count";
 	}
 
 	return "unknown";
 }
 
 static struct ndb_blocks *ndb_note_to_blocks(struct ndb_note *note)
 {
 	const char *content;
 	size_t content_len;
 	struct ndb_blocks *blocks;
 
 	content = ndb_note_content(note);
 	content_len = ndb_note_content_length(note);
 
 	// something weird is going on
 	if (content_len >= INT32_MAX)
 		return NULL;
 
 	unsigned char *buffer = malloc(content_len);
 	if (!buffer)
 		return NULL;
 
 	if (!ndb_parse_content(buffer, content_len, content, content_len, &blocks)) {
 		free(buffer);
 		return NULL;
 	}
 
 	//blocks = realloc(blocks, ndb_blocks_total_size(blocks));
 	//if (blocks == NULL)
 		//return NULL;
 
 	blocks->flags |= NDB_BLOCK_FLAG_OWNED;
 
 	return blocks;
 }
 
 struct ndb_blocks *ndb_get_blocks_by_key(struct ndb *ndb, struct ndb_txn *txn, uint64_t note_key)
 {
 	struct ndb_blocks *blocks, *blocks_to_writer;
 	size_t blocks_size;
 	struct ndb_note *note;
 	size_t note_len;
 
 	if ((blocks = ndb_lookup_by_key(txn, note_key, NDB_DB_NOTE_BLOCKS, &note_len))) {
 		return blocks;
 	}
 
 	// If we don't have note blocks, let's lazily generate them. This is
 	// migration-friendly instead of doing them all at once
 	if (!(note = ndb_get_note_by_key(txn, note_key, &note_len))) {
 		// no note found, can't return note blocks
 		return NULL;
 	}
 
 	 if (!(blocks = ndb_note_to_blocks(note)))
 		 return NULL;
 
 	 // send a copy to the writer
 	 blocks_size = ndb_blocks_total_size(blocks);
 	 blocks_to_writer = malloc(blocks_size);
 	 memcpy(blocks_to_writer, blocks, blocks_size);
 	 assert(blocks->flags & NDB_BLOCK_FLAG_OWNED);
 
 	 // we generated new blocks, let's store them in the DB
 	 struct ndb_writer_blocks write_blocks = {
 		 .blocks = blocks_to_writer,
 		 .note_key = note_key
 	 };
 
 	 assert(write_blocks.blocks != blocks);
 
 	 struct ndb_writer_msg msg = { .type = NDB_WRITER_BLOCKS };
 	 msg.blocks = write_blocks;
 
 	 ndb_writer_queue_msg(&ndb->writer, &msg);
 
 	 return blocks;
 }
 
 // please call ndb_monitor_lock before calling this
 static struct ndb_subscription *
 ndb_monitor_find_subscription(struct ndb_monitor *monitor, uint64_t subid, int *index)
 {
 	struct ndb_subscription *sub, *tsub;
 	int i;
 
 	for (i = 0, sub = NULL; i < monitor->num_subscriptions; i++) {
 		tsub = &monitor->subscriptions[i];
 		if (tsub->subid == subid) {
 			sub = tsub;
 			if (index)
 				*index = i;
 			break;
 		}
 	}
 
 	return sub;
 }
 
 int ndb_poll_for_notes(struct ndb *ndb, uint64_t subid, uint64_t *note_ids,
 		       int note_id_capacity)
 {
 	struct ndb_subscription *sub;
 	int res;
 
 	if (subid == 0)
 		return 0;
 
 	ndb_monitor_lock(&ndb->monitor);
 
 	if (!(sub = ndb_monitor_find_subscription(&ndb->monitor, subid, NULL)))
 		res = 0;
 	else
 		res = prot_queue_try_pop_all(&sub->inbox, note_ids, note_id_capacity);
 
 	ndb_monitor_unlock(&ndb->monitor);
 
 	return res;
 }
 
 int ndb_wait_for_notes(struct ndb *ndb, uint64_t subid, uint64_t *note_ids,
                        int note_id_capacity)
 {
 	struct ndb_subscription *sub;
 	struct prot_queue *queue_inbox;
 
         // this is not a valid subscription id
 	if (subid == 0)
 		return 0;
 
 	ndb_monitor_lock(&ndb->monitor);
 
         if (!(sub = ndb_monitor_find_subscription(&ndb->monitor, subid, NULL))) {
 		ndb_monitor_unlock(&ndb->monitor);
 		return 0;
 	}
 
 	queue_inbox = &sub->inbox;
 
 	ndb_monitor_unlock(&ndb->monitor);
 
 	// there is technically a race condition if the thread yeilds at this
 	// comment and a subscription is added/removed. A deadlock in the
 	// writer queue would be much worse though. This function is dubious
 	// anyways.
 
         return prot_queue_pop_all(queue_inbox, note_ids, note_id_capacity);
 }
 
 int ndb_unsubscribe(struct ndb *ndb, uint64_t subid)
 {
 	struct ndb_subscription *sub;
 	int index, res, elems_to_move;
 
 	ndb_monitor_lock(&ndb->monitor);
 
 	if (!(sub = ndb_monitor_find_subscription(&ndb->monitor, subid, &index))) {
 		res = 0;
 		goto done;
 	}
 
 	ndb_subscription_destroy(sub);
 
 	elems_to_move = (--ndb->monitor.num_subscriptions) - index;
 
 	memmove(&ndb->monitor.subscriptions[index],
 		&ndb->monitor.subscriptions[index+1],
 		elems_to_move * sizeof(*sub));
 
 	res = 1;
 
 done:
 	ndb_monitor_unlock(&ndb->monitor);
 
 	return res;
 }
 
 int ndb_num_subscriptions(struct ndb *ndb)
 {
 	return ndb->monitor.num_subscriptions;
 }
 
 uint64_t ndb_subscribe(struct ndb *ndb, struct ndb_filter *filters, int num_filters)
 {
 	static uint64_t subids = 0;
 	struct ndb_subscription *sub;
 	size_t buflen;
 	uint64_t subid;
 	char *buf;
 
 	ndb_monitor_lock(&ndb->monitor);
 
 	if (ndb->monitor.num_subscriptions + 1 >= MAX_SUBSCRIPTIONS) {
 		fprintf(stderr, "too many subscriptions\n");
 		subid = 0;
 		goto done;
 	}
 
 	sub = &ndb->monitor.subscriptions[ndb->monitor.num_subscriptions];
 	subid = ++subids;
 	sub->subid = subid;
 
 	ndb_filter_group_init(&sub->group);
 	if (!ndb_filter_group_add_filters(&sub->group, filters, num_filters)) {
 		subid = 0;
 		goto done;
 	}
 
 	// 500k ought to be enough for anyone
 	buflen = sizeof(uint64_t) * DEFAULT_QUEUE_SIZE;
 	buf = malloc(buflen);
 
 	if (!prot_queue_init(&sub->inbox, buf, buflen, sizeof(uint64_t))) {
 		fprintf(stderr, "failed to push prot queue\n");
 		subid = 0;
 		goto done;
 	}
 
 	ndb->monitor.num_subscriptions++;
 done:
 	ndb_monitor_unlock(&ndb->monitor);
 
 	return subid;
 }