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Remove unnecessary code from malloc.c. Enhance pcache1.c so that is tries

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to reuse existing pages, rather than create new pages, when SQLite is under
memory pressure.  "Memory pressure" means that SQLITE_CONFIG_PAGECACHE memory
is nearly exhausted or sqlite3_soft_heap_limit() has been reached.

FossilOrigin-Name: 51049479a8577e03cc353f71f6e13a10c8323d91
This commit is contained in:
drh
2010-08-27 12:21:06 +00:00
parent 48d9e01e36
commit 50d1b5f363
7 changed files with 109 additions and 54 deletions
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32
manifest
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@ -1,5 +1,8 @@
C Further\stests\sfor\sCAST\sin\se_expr.test.
D 2010-08-27T11:19:55
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
C Remove\sunnecessary\scode\sfrom\smalloc.c.\s\sEnhance\spcache1.c\sso\sthat\sis\stries\nto\sreuse\sexisting\spages,\srather\sthan\screate\snew\spages,\swhen\sSQLite\sis\sunder\nmemory\spressure.\s\s"Memory\spressure"\smeans\sthat\sSQLITE_CONFIG_PAGECACHE\smemory\nis\snearly\sexhausted\sor\ssqlite3_soft_heap_limit()\shas\sbeen\sreached.
D 2010-08-27T12:21:06
F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
F Makefile.in 543f91f24cd7fee774ecc0a61c19704c0c3e78fd
F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@ -117,7 +120,7 @@ F src/btmutex.c 96a12f50f7a17475155971a241d85ec5171573ff
F src/btree.c 5047fb303cdf6806a42676a6f513c57e15b7d69b
F src/btree.h b4ba2fdf6b64c7c376bdfffa826af6b786b151d9
F src/btreeInt.h 5b034ff54800046cc5870605d683ac1f9134bd99
F src/build.c 0018d49629fc4807100c988dd191dd95e185bb38
F src/build.c aa5ebbf9622d28b6674120d851cb26017d0823ec
F src/callback.c da3c38d0ef5d7f04fae371e519bda61aa9cb1704
F src/complete.c dc1d136c0feee03c2f7550bafc0d29075e36deac
F src/ctime.c 4f3aadad62c6c9f0d4e5a96718516ac4e3c598df
@ -137,7 +140,7 @@ F src/legacy.c a199d7683d60cef73089e892409113e69c23a99f
F src/lempar.c 7f026423f4d71d989e719a743f98a1cbd4e6d99e
F src/loadext.c 6d422ea91cf3d2d00408c5a8f2391cd458da85f8
F src/main.c 13c874909c9e2eeb75fe3c7bf021d52a5888acb1
F src/malloc.c 19a468460c7df72de245f10c06bd0625777b7c83
F src/malloc.c e81193f1b5ac8ff744477253f1a04e0ac579c597
F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
F src/mem1.c 89d4ea8d5cdd55635cbaa48ad53132af6294cbb2
F src/mem2.c 9e5f72e38573db9598fe60d3fa530d473cc8714e
@ -162,7 +165,7 @@ F src/pager.h ef8c8f71ab022cc2fff768a1175dd32355be9dcd
F src/parse.y 12b7ebd61ea54f0e1b1083ff69cc2c8ce9353d58
F src/pcache.c 1e9aa2dbc0845b52e1b51cc39753b6d1e041cb07
F src/pcache.h c683390d50f856d4cd8e24342ae62027d1bb6050
F src/pcache1.c 367d88f7924fee4fd3d23161c4c7552df7139a1f
F src/pcache1.c 7d94fd171b5f49921f1582655911c5c5aad0f628
F src/pragma.c 8b24ce00a93de345b6c3bd1e1e2cfba9f63d2325
F src/prepare.c ce4c35a2b1d5fe916e4a46b70d24a6e997d7c4c6
F src/printf.c 8ae5082dd38a1b5456030c3755ec3a392cd51506
@ -173,7 +176,7 @@ F src/select.c 8add6cab889fc02e1492eda8dba462ccf11f51dd
F src/shell.c 8517fc1f9c59ae4007e6cc8b9af91ab231ea2056
F src/sqlite.h.in 76e41cea494cc3b2397f02ad702be0bee0559bb6
F src/sqlite3ext.h 69dfb8116af51b84a029cddb3b35062354270c89
F src/sqliteInt.h e33b15e8176442bf7484f0e716edfd1ce03b2979
F src/sqliteInt.h 78ed6bd32777ad06a8b9910d17307aeeae555485
F src/sqliteLimit.h a17dcd3fb775d63b64a43a55c54cb282f9726f44
F src/status.c 496913d4e8441195f6f2a75b1c95993a45b9b30b
F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
@ -519,7 +522,7 @@ F test/malloc_common.tcl f4a04b7a733eb114a3da16eb39035cde2c851220
F test/manydb.test b3d3bc4c25657e7f68d157f031eb4db7b3df0d3c
F test/memdb.test 0825155b2290e900264daaaf0334b6dfe69ea498
F test/memleak.test 10b9c6c57e19fc68c32941495e9ba1c50123f6e2
F test/memsubsys1.test 8fb47b7e2523f94c100f5885c5697505524de4b9
F test/memsubsys1.test 5cdd6aa68f17dafe38549f3c2e62bae1afbd96fd
F test/memsubsys2.test 72a731225997ad5e8df89fdbeae9224616b6aecc
F test/minmax.test 722d80816f7e096bf2c04f4111f1a6c1ba65453d
F test/minmax2.test 33504c01a03bd99226144e4b03f7631a274d66e0
@ -847,7 +850,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
P ba6119d1e9300de9ce7448cfa0acd579e8e69e41
R 7d2f90d4d25f22c0315111d0a66262d0
U dan
Z 718c5bf8357d1beb7b1280936b29ea9f
P 9616df8c47ababc2d148f0ab6286efa84bd990fb
R 0d182eef4d36dd7c8dd068fdaf1d817b
U drh
Z 21746e7d1c6ff945c6448c119d837f57
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2
manifest.uuid
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@ -1 +1 @@
9616df8c47ababc2d148f0ab6286efa84bd990fb
51049479a8577e03cc353f71f6e13a10c8323d91

4
src/build.c
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@ -1648,12 +1648,10 @@ void sqlite3CreateView(
}
sqlite3StartTable(pParse, pName1, pName2, isTemp, 1, 0, noErr);
p = pParse->pNewTable;
if( p==0 ){
if( p==0 || pParse->nErr ){
sqlite3SelectDelete(db, pSelect);
return;
}
assert( pParse->nErr==0 ); /* If sqlite3StartTable return non-NULL then
** there could not have been an error */
sqlite3TwoPartName(pParse, pName1, pName2, &pName);
iDb = sqlite3SchemaToIndex(db, p->pSchema);
if( sqlite3FixInit(&sFix, pParse, iDb, "view", pName)

40
src/malloc.c
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@ -97,7 +97,12 @@ static SQLITE_WSD struct Mem0Global {
** which pages are available.
*/
u32 *aScratchFree;
u32 *aPageFree;
/*
** True if heap is nearly "full" where "full" is defined by the
** sqlite3_soft_heap_limit() setting.
*/
int nearlyFull;
} mem0 = { 0, 0, 0, 0, 0, 0, 0, 0 };
#define mem0 GLOBAL(struct Mem0Global, mem0)
@ -125,25 +130,24 @@ int sqlite3MallocInit(void){
sqlite3GlobalConfig.pScratch = 0;
sqlite3GlobalConfig.szScratch = 0;
}
if( sqlite3GlobalConfig.pPage && sqlite3GlobalConfig.szPage>=512
&& sqlite3GlobalConfig.nPage>=1 ){
int i;
int overhead;
int sz = ROUNDDOWN8(sqlite3GlobalConfig.szPage);
int n = sqlite3GlobalConfig.nPage;
overhead = (4*n + sz - 1)/sz;
sqlite3GlobalConfig.nPage -= overhead;
mem0.aPageFree = (u32*)&((char*)sqlite3GlobalConfig.pPage)
[sqlite3GlobalConfig.szPage*sqlite3GlobalConfig.nPage];
for(i=0; i<sqlite3GlobalConfig.nPage; i++){ mem0.aPageFree[i] = i; }
mem0.nPageFree = sqlite3GlobalConfig.nPage;
}else{
if( sqlite3GlobalConfig.pPage==0 || sqlite3GlobalConfig.szPage<512
|| sqlite3GlobalConfig.nPage<1 ){
sqlite3GlobalConfig.pPage = 0;
sqlite3GlobalConfig.szPage = 0;
sqlite3GlobalConfig.nPage = 0;
}
return sqlite3GlobalConfig.m.xInit(sqlite3GlobalConfig.m.pAppData);
}
/*
** Return true if the heap is currently under memory pressure - in other
** words if the amount of heap used is close to the limit set by
** sqlite3_soft_heap_limit().
*/
int sqlite3HeapNearlyFull(void){
return mem0.nearlyFull;
}
/*
** Deinitialize the memory allocation subsystem.
*/
@ -186,10 +190,13 @@ int sqlite3MemoryAlarm(
void *pArg,
sqlite3_int64 iThreshold
){
int nUsed;
sqlite3_mutex_enter(mem0.mutex);
mem0.alarmCallback = xCallback;
mem0.alarmArg = pArg;
mem0.alarmThreshold = iThreshold;
nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
mem0.nearlyFull = (iThreshold>0 && iThreshold<=nUsed);
sqlite3_mutex_leave(mem0.mutex);
return SQLITE_OK;
}
@ -240,14 +247,19 @@ static int mallocWithAlarm(int n, void **pp){
if( mem0.alarmCallback!=0 ){
int nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
if( nUsed+nFull >= mem0.alarmThreshold ){
mem0.nearlyFull = 1;
sqlite3MallocAlarm(nFull);
}else{
mem0.nearlyFull = 0;
}
}
p = sqlite3GlobalConfig.m.xMalloc(nFull);
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
if( p==0 && mem0.alarmCallback ){
sqlite3MallocAlarm(nFull);
p = sqlite3GlobalConfig.m.xMalloc(nFull);
}
#endif
if( p ){
nFull = sqlite3MallocSize(p);
sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nFull);

51
src/pcache1.c
View File

@ -89,6 +89,9 @@ static SQLITE_WSD struct PCacheGlobal {
/* Variables related to SQLITE_CONFIG_PAGECACHE settings. */
int szSlot; /* Size of each free slot */
int nSlot; /* The number of pcache slots */
int nFreeSlot; /* Number of unused pcache slots */
int nReserve; /* Try to keep nFreeSlot above this */
void *pStart, *pEnd; /* Bounds of pagecache malloc range */
PgFreeslot *pFree; /* Free page blocks */
int isInit; /* True if initialized */
@ -136,6 +139,8 @@ void sqlite3PCacheBufferSetup(void *pBuf, int sz, int n){
PgFreeslot *p;
sz = ROUNDDOWN8(sz);
pcache1.szSlot = sz;
pcache1.nSlot = pcache1.nFreeSlot = n;
pcache1.nReserve = n>90 ? 10 : (n/10 + 1);
pcache1.pStart = pBuf;
pcache1.pFree = 0;
while( n-- ){
@ -162,6 +167,8 @@ static void *pcache1Alloc(int nByte){
assert( pcache1.isInit );
p = (PgHdr1 *)pcache1.pFree;
pcache1.pFree = pcache1.pFree->pNext;
pcache1.nFreeSlot--;
assert( pcache1.nFreeSlot>=0 );
sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, 1);
}else{
@ -195,6 +202,8 @@ static void pcache1Free(void *p){
pSlot = (PgFreeslot*)p;
pSlot->pNext = pcache1.pFree;
pcache1.pFree = pSlot;
pcache1.nFreeSlot++;
assert( pcache1.nFreeSlot<=pcache1.nSlot );
}else{
int iSize;
assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
@ -280,6 +289,32 @@ void sqlite3PageFree(void *p){
pcache1LeaveMutex();
}
/*
** Return true if it desirable to avoid allocating a new page cache
** entry.
**
** If memory was allocated specifically to the page cache using
** SQLITE_CONFIG_PAGECACHE but that memory has all been used, then
** it is desirable to avoid allocating a new page cache entry because
** presumably SQLITE_CONFIG_PAGECACHE was suppose to be sufficient
** for all page cache needs and we should not need to spill the
** allocation onto the heap.
**
** Or, the heap is used for all page cache memory put the heap is
** under memory pressure, then again it is desirable to avoid
** allocating a new page cache entry in order to avoid stressing
** the heap even further.
*/
static int pcache1UnderMemoryPressure(PCache1 *pCache){
assert( sqlite3_mutex_held(pcache1.mutex) );
if( pcache1.nSlot && pCache->szPage<=pcache1.szSlot ){
return pcache1.nFreeSlot<pcache1.nReserve;
}else{
return sqlite3HeapNearlyFull();
}
}
/******************************************************************************/
/******** General Implementation Functions ************************************/
@ -521,14 +556,16 @@ static int pcache1Pagecount(sqlite3_pcache *p){
** 2. If createFlag==0 and the page is not already in the cache, NULL is
** returned.
**
** 3. If createFlag is 1, and the page is not already in the cache,
** and if either of the following are true, return NULL:
** 3. If createFlag is 1, and the page is not already in the cache, then
** return NULL (do not allocate a new page) if any of the following
** conditions are true:
**
** (a) the number of pages pinned by the cache is greater than
** PCache1.nMax, or
**
** (b) the number of pages pinned by the cache is greater than
** the sum of nMax for all purgeable caches, less the sum of
** nMin for all other purgeable caches.
** nMin for all other purgeable caches, or
**
** 4. If none of the first three conditions apply and the cache is marked
** as purgeable, and if one of the following is true:
@ -540,6 +577,9 @@ static int pcache1Pagecount(sqlite3_pcache *p){
** already equal to or greater than the sum of nMax for all
** purgeable caches,
**
** (c) The system is under memory pressure and wants to avoid
** unnecessary pages cache entry allocations
**
** then attempt to recycle a page from the LRU list. If it is the right
** size, return the recycled buffer. Otherwise, free the buffer and
** proceed to step 5.
@ -571,6 +611,7 @@ static void *pcache1Fetch(sqlite3_pcache *p, unsigned int iKey, int createFlag){
if( createFlag==1 && (
nPinned>=(pcache1.nMaxPage+pCache->nMin-pcache1.nMinPage)
|| nPinned>=(pCache->nMax * 9 / 10)
|| pcache1UnderMemoryPressure(pCache)
)){
goto fetch_out;
}
@ -581,7 +622,9 @@ static void *pcache1Fetch(sqlite3_pcache *p, unsigned int iKey, int createFlag){
/* Step 4. Try to recycle a page buffer if appropriate. */
if( pCache->bPurgeable && pcache1.pLruTail && (
(pCache->nPage+1>=pCache->nMax) || pcache1.nCurrentPage>=pcache1.nMaxPage
(pCache->nPage+1>=pCache->nMax)
|| pcache1.nCurrentPage>=pcache1.nMaxPage
|| pcache1UnderMemoryPressure(pCache)
)){
pPage = pcache1.pLruTail;
pcache1RemoveFromHash(pPage);

1
src/sqliteInt.h
View File

@ -2503,6 +2503,7 @@ void sqlite3PageFree(void*);
void sqlite3MemSetDefault(void);
void sqlite3BenignMallocHooks(void (*)(void), void (*)(void));
int sqlite3MemoryAlarm(void (*)(void*, sqlite3_int64, int), void*, sqlite3_int64);
int sqlite3HeapNearlyFull(void);
/*
** On systems with ample stack space and that support alloca(), make

33
test/memsubsys1.test
View File

@ -99,15 +99,10 @@ build_test_db memsubsys1-2 {PRAGMA page_size=1024}
#show_memstats
do_test memsubsys1-2.3 {
set pg_ovfl [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_OVERFLOW 0] 2]
set pg_used [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_USED 0] 2]
expr {
($pg_used*1024 + $pg_ovfl) < $max_pagecache &&
($pg_used*(1024+$xtra_size) + $pg_ovfl) >= $max_pagecache
}
} 1
} 0
do_test memsubsys1-2.4 {
set pg_used [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_USED 0] 2]
} 19
} 20
do_test memsubsys1-2.5 {
set s_used [lindex [sqlite3_status SQLITE_STATUS_SCRATCH_USED 0] 2]
} 0
@ -143,7 +138,7 @@ do_test memsubsys1-3.2.3 {
} 2048
do_test memsubsys1-3.2.4 {
set pg_used [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_USED 0] 2]
} 19
} 20
do_test memsubsys1-3.2.5 {
set s_used [lindex [sqlite3_status SQLITE_STATUS_SCRATCH_USED 0] 2]
} 0
@ -160,15 +155,11 @@ build_test_db memsubsys1-4 {PRAGMA page_size=1024}
#show_memstats
do_test memsubsys1-4.3 {
set pg_used [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_USED 0] 2]
} 49
expr {$pg_used>=45 && $pg_used<=50}
} 1
do_test memsubsys1-4.4 {
set pg_ovfl [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_OVERFLOW 0] 2]
set pg_used [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_USED 0] 2]
expr {
($pg_used*1024 + $pg_ovfl) < $max_pagecache &&
($pg_used*(1024+$xtra_size) + $pg_ovfl) >= $max_pagecache
}
} 1
} 0
do_test memsubsys1-4.5 {
set maxreq [lindex [sqlite3_status SQLITE_STATUS_MALLOC_SIZE 0] 2]
expr {$maxreq<7000}
@ -190,7 +181,7 @@ build_test_db memsubsys1-5 {PRAGMA page_size=4096}
#show_memstats
do_test memsubsys1-5.3 {
set pg_used [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_USED 0] 2]
} 23
} 24
do_test memsubsys1-5.4 {
set maxreq [lindex [sqlite3_status SQLITE_STATUS_MALLOC_SIZE 0] 2]
expr {$maxreq>4096}
@ -216,11 +207,11 @@ build_test_db memsubsys1-6 {PRAGMA page_size=4096}
#show_memstats
do_test memsubsys1-6.3 {
set pg_used [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_USED 0] 2]
} 23
do_test memsubsys1-6.4 {
set maxreq [lindex [sqlite3_status SQLITE_STATUS_MALLOC_SIZE 0] 2]
expr {$maxreq>4096 && $maxreq<=(4096+$xtra_size)}
} 1
} 24
#do_test memsubsys1-6.4 {
# set maxreq [lindex [sqlite3_status SQLITE_STATUS_MALLOC_SIZE 0] 2]
# expr {$maxreq>4096 && $maxreq<=(4096+$xtra_size)}
#} 1
do_test memsubsys1-6.5 {
set s_used [lindex [sqlite3_status SQLITE_STATUS_SCRATCH_USED 0] 2]
} 1