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Template and prepared statement caching

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cozis
2025-08-16 17:28:38 +02:00
parent 67d1eb2304
commit 7baba9657d
15 changed files with 963 additions and 433 deletions
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src/sqlite3utils.c
+139 -26
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@@ -1,42 +1,155 @@
#include <stdio.h>
#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include "sqlite3utils.h"
int sqlite3utils_prepare_impl(sqlite3 *db, sqlite3_stmt **pstmt, const char *fmt, VArgs args)
typedef struct {
char *str;
int len;
sqlite3_stmt *stmt;
} Prepped;
struct SQLiteCache {
sqlite3 *db;
int count;
int capacity_log2;
Prepped items[];
};
SQLiteCache *sqlite_cache_init(sqlite3 *db, int capacity_log2)
{
SQLiteCache *cache = malloc(sizeof(SQLiteCache) + (1 << capacity_log2) * sizeof(Prepped));
if (cache == NULL)
return NULL;
cache->db = db;
cache->count = 0;
cache->capacity_log2 = capacity_log2;
for (int i = 0; i < (1 << capacity_log2); i++)
cache->items[i].stmt = NULL;
return cache;
}
void sqlite_cache_free(SQLiteCache *cache)
{
for (int i = 0; i < (1 << cache->capacity_log2); i++) {
sqlite3_stmt *stmt = cache->items[i].stmt;
if (stmt) {
free(cache->items[i].str);
sqlite3_finalize(stmt);
}
}
free(cache);
}
sqlite3 *sqlite_cache_getdb(SQLiteCache *cache)
{
return cache->db;
}
static unsigned long djb2(char *src, int len)
{
char *ptr = src;
char *end = src + len;
unsigned long hash = 5381;
int c;
while (ptr < end && (c = *ptr++))
hash = ((hash << 5) + hash) + c; // hash * 33 + c
return hash;
}
static int lookup(SQLiteCache *cache, char *fmt, int fmtlen)
{
int mask = (1 << cache->capacity_log2) - 1;
int hash = djb2(fmt, fmtlen);
int i = hash & mask;
int perturb = hash;
for (;;) {
if (cache->items[i].stmt == NULL)
return i;
if (cache->items[i].len == fmtlen && !memcmp(cache->items[i].str, fmt, fmtlen))
return i;
perturb >>= 5;
i = (i * 5 + 1 + perturb) & mask;
}
return -1;
}
int sqlite3utils_prepare(SQLiteCache *cache, sqlite3_stmt **pstmt, const char *fmt, int fmtlen)
{
if (fmtlen < 0)
fmtlen = strlen(fmt);
int i = lookup(cache, fmt, fmtlen);
if (cache->items[i].stmt == NULL) {
printf("Preparing statement [%.*s]\n", fmtlen, fmt); // TODO
sqlite3_stmt *stmt;
int ret = sqlite3_prepare_v2(cache->db, fmt, -1, &stmt, NULL);
if (ret != SQLITE_OK) {
//fprintf(stderr, "Failed to prepare statement: %s (%s:%d)\n", sqlite3_errmsg(db), __FILE__, __LINE__);
return ret;
}
char *cpy = malloc(fmtlen);
if (cpy == NULL) {
sqlite3_finalize(stmt);
return SQLITE_NOMEM;
}
memcpy(cpy, fmt, fmtlen);
cache->items[i].str = cpy;
cache->items[i].len = fmtlen;
cache->items[i].stmt = stmt;
}
sqlite3_stmt *stmt = cache->items[i].stmt;
*pstmt = stmt;
return SQLITE_OK;
}
int sqlite3utils_prepare_and_bind_impl(SQLiteCache *cache,
sqlite3_stmt **pstmt, const char *fmt, VArgs args)
{
sqlite3_stmt *stmt;
int ret = sqlite3_prepare_v2(db, fmt, -1, &stmt, NULL);
if (ret != SQLITE_OK) {
fprintf(stderr, "Failed to prepare statement: %s (%s:%d)\n", sqlite3_errmsg(db), __FILE__, __LINE__);
int ret = sqlite3utils_prepare(cache, &stmt, fmt, strlen(fmt));
if (ret != SQLITE_OK)
return ret;
}
for (int i = 0; i < args.len; i++) {
VArg arg = args.ptr[i];
switch (arg.type) {
case VARG_TYPE_C : ret = sqlite3_bind_text(stmt, i+1, &arg.c, 1, NULL); break;
case VARG_TYPE_S : ret = sqlite3_bind_int(stmt, i+1, arg.s); break;
case VARG_TYPE_I : ret = sqlite3_bind_int(stmt, i+1, arg.i); break;
case VARG_TYPE_L : ret = sqlite3_bind_int64(stmt, i+1, arg.l); break;
case VARG_TYPE_LL : ret = sqlite3_bind_int64(stmt, i+1, arg.ll); break;
case VARG_TYPE_SC : ret = sqlite3_bind_int(stmt, i+1, arg.sc); break;
case VARG_TYPE_SS : ret = sqlite3_bind_int(stmt, i+1, arg.ss); break;
case VARG_TYPE_SI : ret = sqlite3_bind_int(stmt, i+1, arg.si); break;
case VARG_TYPE_SL : ret = sqlite3_bind_int64(stmt, i+1, arg.sl); break;
case VARG_TYPE_SLL: ret = sqlite3_bind_int(stmt, i+1, arg.sll); break;
case VARG_TYPE_UC : ret = sqlite3_bind_int(stmt, i+1, arg.uc); break;
case VARG_TYPE_US : ret = sqlite3_bind_int(stmt, i+1, arg.us); break;
case VARG_TYPE_UI : ret = sqlite3_bind_int64(stmt, i+1, arg.ui); break;
case VARG_TYPE_UL : ret = sqlite3_bind_int64(stmt, i+1, arg.ul); break;
case VARG_TYPE_ULL: ret = sqlite3_bind_int64(stmt, i+1, arg.ull); break;
case VARG_TYPE_F : ret = sqlite3_bind_double(stmt, i+1, arg.f); break;
case VARG_TYPE_D : ret = sqlite3_bind_double(stmt, i+1, arg.d); break;
case VARG_TYPE_B : ret = sqlite3_bind_int(stmt, i+1, arg.b); break;
case VARG_TYPE_STR: ret = sqlite3_bind_text(stmt, i+1, arg.str.ptr, arg.str.len, NULL); break;
case VARG_TYPE_C : ret = sqlite3_bind_text (stmt, i+1, &arg.c, 1, NULL); break;
case VARG_TYPE_S : ret = sqlite3_bind_int (stmt, i+1, arg.s); break;
case VARG_TYPE_I : ret = sqlite3_bind_int (stmt, i+1, arg.i); break;
case VARG_TYPE_L : ret = sqlite3_bind_int64 (stmt, i+1, arg.l); break;
case VARG_TYPE_LL : ret = sqlite3_bind_int64 (stmt, i+1, arg.ll); break;
case VARG_TYPE_SC : ret = sqlite3_bind_int (stmt, i+1, arg.sc); break;
case VARG_TYPE_SS : ret = sqlite3_bind_int (stmt, i+1, arg.ss); break;
case VARG_TYPE_SI : ret = sqlite3_bind_int (stmt, i+1, arg.si); break;
case VARG_TYPE_SL : ret = sqlite3_bind_int64 (stmt, i+1, arg.sl); break;
case VARG_TYPE_SLL: ret = sqlite3_bind_int (stmt, i+1, arg.sll); break;
case VARG_TYPE_UC : ret = sqlite3_bind_int (stmt, i+1, arg.uc); break;
case VARG_TYPE_US : ret = sqlite3_bind_int (stmt, i+1, arg.us); break;
case VARG_TYPE_UI : ret = sqlite3_bind_int64 (stmt, i+1, arg.ui); break;
case VARG_TYPE_UL : ret = sqlite3_bind_int64 (stmt, i+1, arg.ul); break;
case VARG_TYPE_ULL: ret = sqlite3_bind_int64 (stmt, i+1, arg.ull); break;
case VARG_TYPE_F : ret = sqlite3_bind_double(stmt, i+1, arg.f); break;
case VARG_TYPE_D : ret = sqlite3_bind_double(stmt, i+1, arg.d); break;
case VARG_TYPE_B : ret = sqlite3_bind_int (stmt, i+1, arg.b); break;
case VARG_TYPE_STR: ret = sqlite3_bind_text (stmt, i+1, arg.str.ptr, arg.str.len, NULL); break;
}
if (ret != SQLITE_OK) {
fprintf(stderr, "Failed to prepare statement: %s (%s:%d)\n", sqlite3_errmsg(db), __FILE__, __LINE__);
sqlite3_finalize(stmt);
sqlite3_reset(stmt);
return ret;
}
}