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If SQLite is compiled with SQLITE_ENABLE_WAL_BIGHASH defined, use

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hash tables large enough to fit 128K, instead of 4K, entries in the *-shm file.

FossilOrigin-Name: 581efc34624c55832afbf7b691d768d6ddbf2b23d6a190d2fa0dde1b00251454
This commit is contained in:
dan
2025-02-05 17:52:13 +00:00
parent aa6ab16a7b
commit 319b518440
8 changed files with 71 additions and 28 deletions
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37
src/wal.c
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@@ -458,13 +458,21 @@ int sqlite3WalTrace = 0;
** version-2 ("journal_mode=wal2"). Legacy clients may support version-1
** only.
*/
#define WAL_VERSION1 3007000 /* For "journal_mode=wal" */
#define WAL_VERSION2 3021000 /* For "journal_mode=wal2" */
#ifdef SQLITE_ENABLE_WAL_BIGHASH
# define WAL_VERSION1 3007001 /* For "journal_mode=wal" */
# define WAL_VERSION2 3021001 /* For "journal_mode=wal2" */
#else
# define WAL_VERSION1 3007000 /* For "journal_mode=wal" */
# define WAL_VERSION2 3021000 /* For "journal_mode=wal2" */
#endif
#ifdef SQLITE_ENABLE_WAL2NOCKSUM
# undef WAL_VERSION2
# define WAL_VERSION2 3048000 /* For "journal_mode=wal2" sans checksums */
# ifdef SQLITE_ENABLE_WAL_BIGHASH
# define WAL_VERSION2 3048001 /* wal2, big-hash, checksums on frame hdrs */
# else
# define WAL_VERSION2 3048000 /* wal2, big-hash, full checksums */
# endif
# define isNocksum(pWal) isWalMode2(pWal)
#else
# define isNocksum(pWal) 0
@@ -842,7 +850,11 @@ struct Wal {
** Each page of the wal-index mapping contains a hash-table made up of
** an array of HASHTABLE_NSLOT elements of the following type.
*/
typedef u16 ht_slot;
#ifdef SQLITE_ENABLE_WAL_BIGHASH
typedef u32 ht_slot;
#else
typedef u16 ht_slot;
#endif
/*
** This structure is used to implement an iterator that loops through
@@ -879,9 +891,14 @@ struct WalIterator {
** Changing any of these constants will alter the wal-index format and
** create incompatibilities.
*/
#define HASHTABLE_NPAGE 4096 /* Must be power of 2 */
#define HASHTABLE_HASH_1 383 /* Should be prime */
#define HASHTABLE_NSLOT (HASHTABLE_NPAGE*2) /* Must be a power of 2 */
#ifdef SQLITE_ENABLE_WAL_BIGHASH
# define HASHTABLE_BITS 17 /* 128K frames per hash */
#else
# define HASHTABLE_BITS 12 /* 4K frames per hash */
#endif
# define HASHTABLE_NPAGE (1<<HASHTABLE_BITS) /* Must be power of 2 */
# define HASHTABLE_HASH_1 383 /* Should be prime */
# define HASHTABLE_NSLOT (HASHTABLE_NPAGE*2) /* Must be a power of 2 */
/*
** The block of page numbers associated with the first hash-table in a
@@ -2161,11 +2178,13 @@ int sqlite3WalOpen(
assert( 40 == sizeof(WalCkptInfo) );
assert( 120 == WALINDEX_LOCK_OFFSET );
assert( 136 == WALINDEX_HDR_SIZE );
#ifndef SQLITE_ENABLE_WAL_BIGHASH
assert( 4096 == HASHTABLE_NPAGE );
assert( 4062 == HASHTABLE_NPAGE_ONE );
assert( 8192 == HASHTABLE_NSLOT );
assert( 383 == HASHTABLE_HASH_1 );
assert( 32768 == WALINDEX_PGSZ );
#endif
assert( 8 == SQLITE_SHM_NLOCK );
assert( 5 == WAL_NREADER );
assert( 24 == WAL_FRAME_HDRSIZE );
@@ -2380,7 +2399,7 @@ static void walMergesort(
ht_slot *aMerge = 0; /* List to be merged */
int iList; /* Index into input list */
u32 iSub = 0; /* Index into aSub array */
struct Sublist aSub[13]; /* Array of sub-lists */
struct Sublist aSub[HASHTABLE_BITS+1]; /* Array of sub-lists */
memset(aSub, 0, sizeof(aSub));
assert( nList<=HASHTABLE_NPAGE && nList>0 );