From a85f7e36e8fc5aa88625726b113be6704ce3792a Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Thu, 28 Aug 2008 02:26:07 +0000
Subject: [PATCH] Miscellaneous cleanup in the new pcache code. (CVS 5629)
FossilOrigin-Name: da1777259f53c2e20c7ced06bf6f2a550f0ea0fc
---
manifest | 20 ++--
manifest.uuid | 2 +-
src/pager.c | 9 +-
src/pcache.c | 274 ++++++++++++++++++++++++++----------------------
src/pcache.h | 22 ++--
src/test_func.c | 7 +-
6 files changed, 183 insertions(+), 151 deletions(-)
diff --git a/manifest b/manifest
index 2b436e05ac..ad116edebf 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C If\sany\serror\soccurs\sduring\ssqlite3_open(),\smove\sthe\sdatabase\shandle\sinto\s"sick"\sstate.\sWhen\sin\sthe\ssick\sstate\sthe\suser\scan\suse\ssqlite3_errcode()\sand\ssqlite3_errmsg(),\sbut\snot\smuch\selse.\s(CVS\s5628)
-D 2008-08-27T19:01:58
+C Miscellaneous\scleanup\sin\sthe\snew\spcache\scode.\s(CVS\s5629)
+D 2008-08-28T02:26:07
F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
F Makefile.in 689e14735f862a5553bceef206d8c13e29504e44
F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -134,11 +134,11 @@ F src/os_common.h 24525d8b7bce66c374dfc1810a6c9043f3359b60
F src/os_os2.c e391fc95adc744bbdcefd4d11e3066998185a0a0
F src/os_unix.c 4665cef7639dd937893c3ea076f0e8a8f215bb32
F src/os_win.c aefe9ee26430678a19a058a874e4e2bd91398142
-F src/pager.c 84f4c171a0cb4561291f212508b1a91a8a325abb
+F src/pager.c 032d11049af4ec49bdbaa3584e7ce9887098b66a
F src/pager.h 914103bb62dbcc3d8e9f14baec812d027264d457
F src/parse.y d0f76d2cb8d6883d5600dc20beb961a6022b94b8
-F src/pcache.c 3d9d933bb22f10956ab78d83798d88ca9a147e86
-F src/pcache.h 7a50b77f06c220ff7696be1a9f2a17c9e6ddc486
+F src/pcache.c aa609c9b1fc1a2b00f7d7bfb3d06b1e507767b93
+F src/pcache.h bd373ee3e4db310d6bbe7fa6d8d971de9678edd8
F src/pragma.c f5b271b090af7fcedd308d7c5807a5503f7a853d
F src/prepare.c c197041e0c4770672cda75e6bfe10242f885e510
F src/printf.c 785f87120589c1db672e37c6eb1087c456e6f84d
@@ -167,7 +167,7 @@ F src/test_autoext.c f53b0cdf7bf5f08100009572a5d65cdb540bd0ad
F src/test_btree.c 7170e0c922ed3979f2d38f4a3f84728e5740dfc3
F src/test_config.c 224f699a34d45eb8ac5c22a7ad6cdbb8edf0ba28
F src/test_devsym.c 6012cb8e3acf812513511025a4fa5d626e0ba19b
-F src/test_func.c bc648b7747320e037d756acfa1037bd8dedf3f8b
+F src/test_func.c a55c4d5479ff2eb5c0a22d4d88e9528ab59c953b
F src/test_hexio.c 2f1122aa3f012fa0142ee3c36ce5c902a70cd12f
F src/test_loadext.c 97dc8800e46a46ed002c2968572656f37e9c0dd9
F src/test_malloc.c 49abbf5d9c71fb06cf7a7cf96f9b9a799b77a421
@@ -624,7 +624,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
F tool/speedtest8.c 1dbced29de5f59ba2ebf877edcadf171540374d1
F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 39c34e2238c27b2a2f4f0b896126ccbd299114c5
-R 0bf03a77bd82f6ac6f412ad9339ae6a4
-U danielk1977
-Z ac6800a3d7725cc034896ca6e2243181
+P ce9c74eaab459ddde213c828e821940f5d6cb354
+R 55c280ec697a3a6039a240cf488ad9ad
+U drh
+Z 7df830e688305e6be422e59df78b53fe
diff --git a/manifest.uuid b/manifest.uuid
index 9e981efe54..609a5bfb32 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-ce9c74eaab459ddde213c828e821940f5d6cb354
\ No newline at end of file
+da1777259f53c2e20c7ced06bf6f2a550f0ea0fc
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index b5296fbcd6..9b063b7b2c 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -18,7 +18,7 @@
** file simultaneously, or one process from reading the database while
** another is writing.
**
-** @(#) $Id: pager.c,v 1.484 2008/08/27 18:03:20 drh Exp $
+** @(#) $Id: pager.c,v 1.485 2008/08/28 02:26:07 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -3271,15 +3271,14 @@ static int pager_write(PgHdr *pPg){
&& !pageInStatement(pPg)
&& (int)pPg->pgno<=pPager->stmtSize
){
- assert(
- (pPg->flags&PGHDR_IN_JOURNAL) || (int)pPg->pgno>pPager->origDbSize );
+ assert( (pPg->flags&PGHDR_IN_JOURNAL)
+ || (int)pPg->pgno>pPager->origDbSize );
if( MEMDB ){
rc = sqlite3PcachePreserve(pPg, 1);
if( rc!=SQLITE_OK ){
return rc;
}
PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
- /* page_add_to_stmt_list(pPg); */
}else{
i64 offset = pPager->stmtNRec*(4+pPager->pageSize);
char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
@@ -3507,7 +3506,7 @@ void sqlite3PagerDontRollback(DbPage *pPg){
assert( !MEMDB ); /* For a memdb, pPager->journalOpen is always 0 */
#ifdef SQLITE_SECURE_DELETE
- if( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize ){
+ if( (pPg->flags & PGHDR_IN_JOURNAL)!=0 || (int)pPg->pgno>pPager->origDbSize ){
return;
}
#endif
diff --git a/src/pcache.c b/src/pcache.c
index b0127120b4..50616bf88b 100644
--- a/src/pcache.c
+++ b/src/pcache.c
@@ -11,30 +11,50 @@
*************************************************************************
** This file implements that page cache.
**
-** @(#) $Id: pcache.c,v 1.18 2008/08/27 16:38:57 danielk1977 Exp $
+** @(#) $Id: pcache.c,v 1.19 2008/08/28 02:26:07 drh Exp $
*/
#include "sqliteInt.h"
/*
** A complete page cache is an instance of this structure.
+**
+** A cache may only be deleted by its owner and while holding the
+** SQLITE_MUTEX_STATUS_LRU mutex.
*/
struct PCache {
- int szPage; /* Size of every page in this cache */
- int szExtra; /* Size of extra space for each page */
- int nHash; /* Number of slots in apHash[] */
- int nPage; /* Total number of pages in apHash */
- int nMax; /* Configured cache size */
- int nMin; /* Configured minimum cache size */
- PgHdr **apHash; /* Hash table for fast lookup by pgno */
- int bPurgeable; /* True if pages are on backing store */
- void (*xDestroy)(PgHdr*); /* Called when refcnt goes 1->0 */
- int (*xStress)(void*,PgHdr*); /* Call to try make a page clean */
- void *pStress; /* Argument to xStress */
- PgHdr *pClean; /* List of clean pages in use */
+ /*********************************************************************
+ ** The first group of elements may be read or written at any time by
+ ** the cache owner without holding the mutex. No thread other than the
+ ** cache owner is permitted to access these elements at any time.
+ */
PgHdr *pDirty, *pDirtyTail; /* List of dirty pages in LRU order */
PgHdr *pSynced; /* Last synced page in dirty page list */
int nRef; /* Number of pinned pages */
int nPinned; /* Number of pinned and/or dirty pages */
+ int nMax; /* Configured cache size */
+ int nMin; /* Configured minimum cache size */
+ /**********************************************************************
+ ** The next group of elements are fixed when the cache is created and
+ ** may not be changed afterwards. These elements can read at any time by
+ ** the cache owner or by any thread holding the the mutex. Non-owner
+ ** threads must hold the mutex when reading these elements to prevent
+ ** the entire PCache object from being deleted during the read.
+ */
+ int szPage; /* Size of every page in this cache */
+ int szExtra; /* Size of extra space for each page */
+ int bPurgeable; /* True if pages are on backing store */
+ void (*xDestroy)(PgHdr*); /* Called when refcnt goes 1->0 */
+ int (*xStress)(void*,PgHdr*); /* Call to try make a page clean */
+ void *pStress; /* Argument to xStress */
+ /**********************************************************************
+ ** The final group of elements can only be accessed while holding the
+ ** mutex. Both the cache owner and any other thread must hold the mutex
+ ** to read or write any of these elements.
+ */
+ int nPage; /* Total number of pages in apHash */
+ int nHash; /* Number of slots in apHash[] */
+ PgHdr **apHash; /* Hash table for fast lookup by pgno */
+ PgHdr *pClean; /* List of clean pages in use */
};
/*
@@ -47,20 +67,6 @@ struct PgFreeslot {
/*
** Global data for the page cache.
-**
-** The maximum number of cached pages stored by the system is determined
-** by the pcache.mxPage and pcache.mxPagePurgeable variables. If
-** mxPage is non-zero, then the system tries to limit the number of
-** cached pages stored to mxPage. In this case mxPagePurgeable is not
-** used.
-**
-** If mxPage is zero, then the system tries to limit the number of
-** pages held by purgable caches to mxPagePurgeable.
-**
-** The doubly-linked list that runs between pcache.pLruHead and
-** pcache.pLruTail contains all clean purgable pages in the system
-** with a zero reference count. pcache.pLruTail is the next page to
-** be recycled.
*/
static struct PCacheGlobal {
int isInit; /* True when initialized */
@@ -78,29 +84,46 @@ static struct PCacheGlobal {
} pcache = {0};
/*
-** All global variables used by this module (most of which are grouped
+** All global variables used by this module (all of which are grouped
** together in global structure "pcache" above) are protected by the static
** SQLITE_MUTEX_STATIC_LRU mutex. A pointer to this mutex is stored in
** variable "pcache.mutex".
**
-** Access to the contents of the individual PCache structures is not
-** protected. It is the job of the caller to ensure that these structures
-** are accessed in a thread-safe manner.
+** Some elements of the PCache and PgHdr structures are protected by the
+** SQLITE_MUTEX_STATUS_LRU mutex and other are not. The protected
+** elements are grouped at the end of the structures and are clearly
+** marked.
+**
+** Use the following macros must surround all access (read or write)
+** of protected elements. The mutex is not recursive and may not be
+** entered more than once. The pcacheMutexHeld() macro should only be
+** used within an assert() to verify that the mutex is being held.
*/
+#define pcacheEnterMutex() sqlite3_mutex_enter(pcache.mutex)
+#define pcacheExitMutex() sqlite3_mutex_leave(pcache.mutex)
+#define pcacheMutexHeld() sqlite3_mutex_held(pcache.mutex)
-#define pcacheEnterGlobal() sqlite3_mutex_enter(pcache.mutex)
-#define pcacheExitGlobal() sqlite3_mutex_leave(pcache.mutex)
+/*
+** Some of the assert() macros in this code are too expensive to run
+** even during normal debugging. Use them only rarely on long-running
+** tests. Enable the expensive asserts using the
+** -DSQLITE_ENABLE_EXPENSIVE_ASSERT=1 compile-time option.
+*/
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+# define expensive_assert(X) assert(X)
+#else
+# define expensive_assert(X)
+#endif
/********************************** Linked List Management ********************/
-#ifndef NDEBUG
+#if !defined(NDEBUG) && defined(SQLITE_ENABLE_EXPENSIVE_ASSERT)
/*
** This routine verifies that the number of entries in the hash table
** is pCache->nPage. This routine is used within assert() statements
** only and is therefore disabled during production builds.
*/
static int pcacheCheckHashCount(PCache *pCache){
-#if 0
int i;
int nPage = 0;
for(i=0; i<pCache->nHash; i++){
@@ -110,19 +133,20 @@ static int pcacheCheckHashCount(PCache *pCache){
}
}
assert( nPage==pCache->nPage );
-#endif
return 1;
}
+#endif /* !NDEBUG && SQLITE_ENABLE_EXPENSIVE_ASSERT */
+
+#if !defined(NDEBUG) && defined(SQLITE_ENABLE_EXPENSIVE_ASSERT)
/*
** Based on the current value of PCache.nRef and the contents of the
** PCache.pDirty list, return the expected value of the PCache.nPinned
** counter. This is only used in debugging builds, as follows:
**
-** assert( pCache->nPinned==pcachePinnedCount(pCache) );
+** expensive_assert( pCache->nPinned==pcachePinnedCount(pCache) );
*/
static int pcachePinnedCount(PCache *pCache){
-#if 0
PgHdr *p;
int nPinned = pCache->nRef;
for(p=pCache->pDirty; p; p=p->pNext){
@@ -131,34 +155,35 @@ static int pcachePinnedCount(PCache *pCache){
}
}
return nPinned;
-#endif
- return pCache->nPinned;
}
+#endif /* !NDEBUG && SQLITE_ENABLE_EXPENSIVE_ASSERT */
+
+#if !defined(NDEBUG) && defined(SQLITE_ENABLE_EXPENSIVE_ASSERT)
/*
** Check that the pCache->pSynced variable is set correctly. If it
** is not, either fail an assert or return zero. Otherwise, return
** non-zero. This is only used in debugging builds, as follows:
**
-** assert( pcacheCheckSynced(pCache) );
+** expensive_assert( pcacheCheckSynced(pCache) );
*/
static int pcacheCheckSynced(PCache *pCache){
-#if 0
PgHdr *p = pCache->pDirtyTail;
for(p=pCache->pDirtyTail; p!=pCache->pSynced; p=p->pPrev){
assert( p->nRef || (p->flags&PGHDR_NEED_SYNC) );
}
return (p==0 || p->nRef || (p->flags&PGHDR_NEED_SYNC)==0);
-#endif
return 1;
}
+#endif /* !NDEBUG && SQLITE_ENABLE_EXPENSIVE_ASSERT */
+
-#endif
/*
** Remove a page from its hash table (PCache.apHash[]).
*/
static void pcacheRemoveFromHash(PgHdr *pPage){
+ /* assert( pcacheMutexHeld() ); *** FIXME ****/
if( pPage->pPrevHash ){
pPage->pPrevHash->pNextHash = pPage->pNextHash;
}else{
@@ -171,15 +196,18 @@ static void pcacheRemoveFromHash(PgHdr *pPage){
pPage->pNextHash->pPrevHash = pPage->pPrevHash;
}
pPage->pCache->nPage--;
- assert( pcacheCheckHashCount(pPage->pCache) );
+ expensive_assert( pcacheCheckHashCount(pPage->pCache) );
}
/*
** Insert a page into the hash table
+**
+** The mutex must be held by the caller.
*/
static void pcacheAddToHash(PgHdr *pPage){
PCache *pCache = pPage->pCache;
u32 h = pPage->pgno % pCache->nHash;
+ /* assert( pcacheMutexHeld() ); *** FIXME *****/
pPage->pNextHash = pCache->apHash[h];
pPage->pPrevHash = 0;
if( pCache->apHash[h] ){
@@ -187,7 +215,7 @@ static void pcacheAddToHash(PgHdr *pPage){
}
pCache->apHash[h] = pPage;
pCache->nPage++;
- assert( pcacheCheckHashCount(pCache) );
+ expensive_assert( pcacheCheckHashCount(pCache) );
}
/*
@@ -195,29 +223,29 @@ static void pcacheAddToHash(PgHdr *pPage){
** at least nHash buckets.
*/
static int pcacheResizeHash(PCache *pCache, int nHash){
+ PgHdr *p;
+ PgHdr **pNew;
+ /* assert( pcacheMutexHeld() ); **** FIXME *****/
#ifdef SQLITE_MALLOC_SOFT_LIMIT
if( nHash*sizeof(PgHdr*)>SQLITE_MALLOC_SOFT_LIMIT ){
nHash = SQLITE_MALLOC_SOFT_LIMIT/sizeof(PgHdr *);
}
#endif
- if( nHash>pCache->nHash ){
- PgHdr *p;
- PgHdr **pNew = (PgHdr **)sqlite3_malloc(sizeof(PgHdr*)*nHash);
- if( !pNew ){
- return SQLITE_NOMEM;
- }
- memset(pNew, 0, sizeof(PgHdr *)*nHash);
- sqlite3_free(pCache->apHash);
- pCache->apHash = pNew;
- pCache->nHash = nHash;
- pCache->nPage = 0;
-
- for(p=pCache->pClean; p; p=p->pNext){
- pcacheAddToHash(p);
- }
- for(p=pCache->pDirty; p; p=p->pNext){
- pcacheAddToHash(p);
- }
+ pNew = (PgHdr **)sqlite3_malloc(sizeof(PgHdr*)*nHash);
+ if( !pNew ){
+ return SQLITE_NOMEM;
+ }
+ memset(pNew, 0, sizeof(PgHdr *)*nHash);
+ sqlite3_free(pCache->apHash);
+ pCache->apHash = pNew;
+ pCache->nHash = nHash;
+ pCache->nPage = 0;
+
+ for(p=pCache->pClean; p; p=p->pNext){
+ pcacheAddToHash(p);
+ }
+ for(p=pCache->pDirty; p; p=p->pNext){
+ pcacheAddToHash(p);
}
return SQLITE_OK;
}
@@ -229,6 +257,7 @@ static int pcacheResizeHash(PCache *pCache, int nHash){
static void pcacheRemoveFromList(PgHdr **ppHead, PgHdr *pPage){
int isDirtyList = (ppHead==&pPage->pCache->pDirty);
assert( ppHead==&pPage->pCache->pClean || ppHead==&pPage->pCache->pDirty );
+ /* assert( pcacheMutexHeld() || ppHead!=&pPage->pCache->pClean ); *** FIXME */
if( pPage->pPrev ){
pPage->pPrev->pNext = pPage->pNext;
@@ -384,13 +413,11 @@ void *pcacheMalloc(int sz, PCache *pCache){
** global pcache mutex and unlock the pager-cache object pCache. This is
** so that if the attempt to allocate a new buffer causes the the
** configured soft-heap-limit to be breached, it will be possible to
- ** reclaim memory from this pager-cache. Because sqlite3PcacheLock()
- ** might block on the MEM2 mutex, it has to be called before re-entering
- ** the global LRU mutex.
+ ** reclaim memory from this pager-cache.
*/
- pcacheExitGlobal();
+ pcacheExitMutex();
p = sqlite3Malloc(sz);
- pcacheEnterGlobal();
+ pcacheEnterMutex();
if( p ){
sz = sqlite3MallocSize(p);
@@ -401,9 +428,9 @@ void *pcacheMalloc(int sz, PCache *pCache){
}
void *sqlite3PageMalloc(sz){
void *p;
- pcacheEnterGlobal();
+ pcacheEnterMutex();
p = pcacheMalloc(sz, 0);
- pcacheExitGlobal();
+ pcacheExitMutex();
return p;
}
@@ -426,9 +453,9 @@ void pcacheFree(void *p){
}
}
void sqlite3PageFree(void *p){
- pcacheEnterGlobal();
+ pcacheEnterMutex();
pcacheFree(p);
- pcacheExitGlobal();
+ pcacheExitMutex();
}
/*
@@ -519,14 +546,14 @@ static int pcacheRecycleOrAlloc(PCache *pCache, PgHdr **ppPage){
assert( sqlite3_mutex_notheld(pcache.mutex) );
*ppPage = 0;
- pcacheEnterGlobal();
+ pcacheEnterMutex();
/* If we have reached the limit for pinned/dirty pages, and there is at
** least one dirty page, invoke the xStress callback to cause a page to
** become clean.
*/
- assert( pCache->nPinned==pcachePinnedCount(pCache) );
- assert( pcacheCheckSynced(pCache) );
+ expensive_assert( pCache->nPinned==pcachePinnedCount(pCache) );
+ expensive_assert( pcacheCheckSynced(pCache) );
if( pCache->xStress
&& pCache->pDirty
&& pCache->nPinned>=(pcache.nMaxPage+pCache->nMin-pcache.nMinPage)
@@ -543,12 +570,12 @@ static int pcacheRecycleOrAlloc(PCache *pCache, PgHdr **ppPage){
}
if( pPg ){
int rc;
- pcacheExitGlobal();
+ pcacheExitMutex();
rc = pCache->xStress(pCache->pStress, pPg);
if( rc!=SQLITE_OK ){
return rc;
}
- pcacheEnterGlobal();
+ pcacheEnterMutex();
}
}
@@ -558,7 +585,7 @@ static int pcacheRecycleOrAlloc(PCache *pCache, PgHdr **ppPage){
}
/* If a page has been recycled but it is the wrong size, free it. */
- if( p && (p->pCache->szPage!=szPage || p->pCache->szExtra!=szExtra) ){
+ if( p && (p->pCache->szPage!=szPage || p->pCache->szPage!=szExtra) ){
pcachePageFree(p);
p = 0;
}
@@ -567,7 +594,7 @@ static int pcacheRecycleOrAlloc(PCache *pCache, PgHdr **ppPage){
p = pcachePageAlloc(pCache);
}
- pcacheExitGlobal();
+ pcacheExitMutex();
*ppPage = p;
return (p?SQLITE_OK:SQLITE_NOMEM);
}
@@ -622,13 +649,13 @@ void sqlite3PcacheOpen(
p->nMax = 100;
p->nMin = 10;
- pcacheEnterGlobal();
+ pcacheEnterMutex();
if( bPurgeable ){
pcache.nMaxPage += p->nMax;
pcache.nMinPage += p->nMin;
}
- pcacheExitGlobal();
+ pcacheExitMutex();
}
/*
@@ -653,7 +680,7 @@ int sqlite3PcacheFetch(
assert( pcache.isInit );
assert( pCache!=0 );
assert( pgno>0 );
- assert( pCache->nPinned==pcachePinnedCount(pCache) );
+ expensive_assert( pCache->nPinned==pcachePinnedCount(pCache) );
/* Search the hash table for the requested page. Exit early if it is found. */
if( pCache->apHash ){
@@ -662,9 +689,9 @@ int sqlite3PcacheFetch(
if( pPage->pgno==pgno ){
if( pPage->nRef==0 ){
if( 0==(pPage->flags&PGHDR_DIRTY) ){
- pcacheEnterGlobal();
+ pcacheEnterMutex();
pcacheRemoveFromLruList(pPage);
- pcacheExitGlobal();
+ pcacheExitMutex();
pCache->nPinned++;
}
pCache->nRef++;
@@ -679,7 +706,7 @@ int sqlite3PcacheFetch(
if( createFlag ){
int rc = SQLITE_OK;
if( pCache->nHash<=pCache->nPage ){
- rc = pcacheResizeHash(pCache, pCache->nHash<256?256:pCache->nHash*2);
+ rc = pcacheResizeHash(pCache, pCache->nHash<256 ? 256 : pCache->nHash*2);
if( rc!=SQLITE_OK ){
return rc;
}
@@ -704,7 +731,7 @@ int sqlite3PcacheFetch(
*ppPage = 0;
}
- assert( pCache->nPinned==pcachePinnedCount(pCache) );
+ expensive_assert( pCache->nPinned==pcachePinnedCount(pCache) );
return SQLITE_OK;
}
@@ -723,9 +750,9 @@ void sqlite3PcacheRelease(PgHdr *p){
pCache->nRef--;
if( (p->flags&PGHDR_DIRTY)==0 ){
pCache->nPinned--;
- pcacheEnterGlobal();
+ pcacheEnterMutex();
pcacheAddToLruList(p);
- pcacheExitGlobal();
+ pcacheExitMutex();
}else{
/* Move the page to the head of the caches dirty list. */
pcacheRemoveFromList(&pCache->pDirty, p);
@@ -753,9 +780,9 @@ void sqlite3PcacheDrop(PgHdr *p){
pCache->nPinned--;
pcacheRemoveFromList(&pCache->pClean, p);
pcacheRemoveFromHash(p);
- pcacheEnterGlobal();
+ pcacheEnterMutex();
pcachePageFree(p);
- pcacheExitGlobal();
+ pcacheExitMutex();
}
/*
@@ -785,15 +812,15 @@ void sqlite3PcacheMakeClean(PgHdr *p){
assert( p->flags & PGHDR_DIRTY );
pCache = p->pCache;
pcacheRemoveFromList(&pCache->pDirty, p);
- pcacheEnterGlobal();
+ pcacheEnterMutex();
pcacheAddToList(&pCache->pClean, p);
p->flags &= ~PGHDR_DIRTY;
if( p->nRef==0 ){
pcacheAddToLruList(p);
pCache->nPinned--;
}
- assert( pCache->nPinned==pcachePinnedCount(pCache) );
- pcacheExitGlobal();
+ expensive_assert( pCache->nPinned==pcachePinnedCount(pCache) );
+ pcacheExitMutex();
}
/*
@@ -801,7 +828,7 @@ void sqlite3PcacheMakeClean(PgHdr *p){
*/
void sqlite3PcacheCleanAll(PCache *pCache){
PgHdr *p;
- pcacheEnterGlobal();
+ pcacheEnterMutex();
while( (p = pCache->pDirty)!=0 ){
assert( p->apSave[0]==0 && p->apSave[1]==0 );
pcacheRemoveFromList(&pCache->pDirty, p);
@@ -813,8 +840,8 @@ void sqlite3PcacheCleanAll(PCache *pCache){
}
}
sqlite3PcacheAssertFlags(pCache, 0, PGHDR_DIRTY);
- assert( pCache->nPinned==pcachePinnedCount(pCache) );
- pcacheExitGlobal();
+ expensive_assert( pCache->nPinned==pcachePinnedCount(pCache) );
+ pcacheExitMutex();
}
/*
@@ -828,10 +855,10 @@ void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
p->pgno = newPgno;
if( newPgno==0 ){
p->flags |= PGHDR_REUSE_UNLIKELY;
- pcacheEnterGlobal();
+ pcacheEnterMutex();
pcacheFree(p->apSave[0]);
pcacheFree(p->apSave[1]);
- pcacheExitGlobal();
+ pcacheExitMutex();
p->apSave[0] = 0;
p->apSave[1] = 0;
sqlite3PcacheMakeClean(p);
@@ -869,7 +896,7 @@ void pcacheClear(PCache *pCache){
void sqlite3PcacheTruncate(PCache *pCache, Pgno pgno){
PgHdr *p, *pNext;
PgHdr *pDirty = pCache->pDirty;
- pcacheEnterGlobal();
+ pcacheEnterMutex();
for(p=pCache->pClean; p||pDirty; p=pNext){
if( !p ){
p = pDirty;
@@ -895,7 +922,7 @@ void sqlite3PcacheTruncate(PCache *pCache, Pgno pgno){
}
}
}
- pcacheExitGlobal();
+ pcacheExitMutex();
}
@@ -903,7 +930,7 @@ void sqlite3PcacheTruncate(PCache *pCache, Pgno pgno){
** Close a cache.
*/
void sqlite3PcacheClose(PCache *pCache){
- pcacheEnterGlobal();
+ pcacheEnterMutex();
/* Free all the pages used by this pager and remove them from the LRU list. */
pcacheClear(pCache);
@@ -913,12 +940,14 @@ void sqlite3PcacheClose(PCache *pCache){
}
sqlite3_free(pCache->apHash);
- pcacheExitGlobal();
+ pcacheExitMutex();
}
/*
-** Preserve the content of the page, if it has not been preserved
-** already. If idJournal==0 then this is for the overall transaction.
+** Preserve the content of the page. It is assumed that the content
+** has not been preserved already.
+**
+** If idJournal==0 then this is for the overall transaction.
** If idJournal==1 then this is for the statement journal.
**
** This routine is used for in-memory databases only.
@@ -929,12 +958,11 @@ int sqlite3PcachePreserve(PgHdr *p, int idJournal){
void *x;
int sz;
assert( p->pCache->bPurgeable==0 );
- if( !p->apSave[idJournal] ){
- sz = p->pCache->szPage;
- p->apSave[idJournal] = x = sqlite3PageMalloc( sz );
- if( x==0 ) return SQLITE_NOMEM;
- memcpy(x, p->pData, sz);
- }
+ assert( p->apSave[idJournal]==0 );
+ sz = p->pCache->szPage;
+ p->apSave[idJournal] = x = sqlite3PageMalloc( sz );
+ if( x==0 ) return SQLITE_NOMEM;
+ memcpy(x, p->pData, sz);
return SQLITE_OK;
}
@@ -943,14 +971,14 @@ int sqlite3PcachePreserve(PgHdr *p, int idJournal){
*/
void sqlite3PcacheCommit(PCache *pCache, int idJournal){
PgHdr *p;
- pcacheEnterGlobal(); /* Mutex is required to call pcacheFree() */
+ pcacheEnterMutex(); /* Mutex is required to call pcacheFree() */
for(p=pCache->pDirty; p; p=p->pNext){
if( p->apSave[idJournal] ){
pcacheFree(p->apSave[idJournal]);
p->apSave[idJournal] = 0;
}
}
- pcacheExitGlobal();
+ pcacheExitMutex();
}
/*
@@ -959,7 +987,7 @@ void sqlite3PcacheCommit(PCache *pCache, int idJournal){
void sqlite3PcacheRollback(PCache *pCache, int idJournal){
PgHdr *p;
int sz;
- pcacheEnterGlobal(); /* Mutex is required to call pcacheFree() */
+ pcacheEnterMutex(); /* Mutex is required to call pcacheFree() */
sz = pCache->szPage;
for(p=pCache->pDirty; p; p=p->pNext){
if( p->apSave[idJournal] ){
@@ -968,7 +996,7 @@ void sqlite3PcacheRollback(PCache *pCache, int idJournal){
p->apSave[idJournal] = 0;
}
}
- pcacheExitGlobal();
+ pcacheExitMutex();
}
/*
@@ -991,9 +1019,9 @@ void sqlite3PcacheAssertFlags(PCache *pCache, int trueMask, int falseMask){
*/
int sqlite3PcacheClear(PCache *pCache){
assert(pCache->nRef==0);
- pcacheEnterGlobal();
+ pcacheEnterMutex();
pcacheClear(pCache);
- pcacheExitGlobal();
+ pcacheExitMutex();
return SQLITE_OK;
}
@@ -1125,7 +1153,7 @@ void sqlite3PcacheSetFlags(PCache *pCache, int andMask, int orMask){
/* Obtain the global mutex before modifying any PgHdr.flags variables
** or traversing the LRU list.
*/
- pcacheEnterGlobal();
+ pcacheEnterMutex();
for(p=pCache->pDirty; p; p=p->pNext){
p->flags = (p->flags&andMask)|orMask;
@@ -1139,7 +1167,7 @@ void sqlite3PcacheSetFlags(PCache *pCache, int andMask, int orMask){
assert( !pCache->pSynced || (pCache->pSynced->flags&PGHDR_NEED_SYNC)==0 );
}
- pcacheExitGlobal();
+ pcacheExitMutex();
}
/*
@@ -1157,10 +1185,10 @@ void sqlite3PcacheSetCachesize(PCache *pCache, int mxPage){
mxPage = 10;
}
if( pCache->bPurgeable ){
- pcacheEnterGlobal();
+ pcacheEnterMutex();
pcache.nMaxPage -= pCache->nMax;
pcache.nMaxPage += mxPage;
- pcacheExitGlobal();
+ pcacheExitMutex();
}
pCache->nMax = mxPage;
}
@@ -1179,12 +1207,12 @@ int sqlite3PcacheReleaseMemory(int nReq){
int nFree = 0;
if( pcache.pStart==0 ){
PgHdr *p;
- pcacheEnterGlobal();
+ pcacheEnterMutex();
while( (nReq<0 || nFree<nReq) && (p=pcacheRecyclePage()) ){
nFree += pcachePageSize(p);
pcachePageFree(p);
}
- pcacheExitGlobal();
+ pcacheExitMutex();
}
return nFree;
}
diff --git a/src/pcache.h b/src/pcache.h
index 8dcc3655aa..d3fd7a9331 100644
--- a/src/pcache.h
+++ b/src/pcache.h
@@ -12,7 +12,7 @@
** This header file defines the interface that the sqlite page cache
** subsystem.
**
-** @(#) $Id: pcache.h,v 1.7 2008/08/27 15:16:34 danielk1977 Exp $
+** @(#) $Id: pcache.h,v 1.8 2008/08/28 02:26:07 drh Exp $
*/
#ifndef _PCACHE_H_
@@ -25,22 +25,30 @@ typedef struct PCache PCache;
** structure.
*/
struct PgHdr {
- u32 flags; /* PGHDR flags defined below */
void *pData; /* Content of this page */
void *pExtra; /* Extra content */
PgHdr *pDirty; /* Transient list of dirty pages */
Pgno pgno; /* Page number for this page */
- Pager *pPager;
+ Pager *pPager; /* The pager this page is part of */
#ifdef SQLITE_CHECK_PAGES
- u32 pageHash;
+ u32 pageHash; /* Hash of page content */
#endif
- /*** Public data is above. All that follows is private to pcache.c ***/
+ u16 flags; /* PGHDR flags defined below */
+ /**********************************************************************
+ ** Elements above are public. All that follows is private to pcache.c
+ ** and should not be accessed by other modules.
+ */
+ i16 nRef; /* Number of users of this page */
PCache *pCache; /* Cache that owns this page */
+ void *apSave[2]; /* Journal entries for in-memory databases */
+ /**********************************************************************
+ ** Elements above are accessible at any time by the owner of the cache
+ ** without the need for a mutex. The elements that follow can only be
+ ** accessed while holding the SQLITE_MUTEX_STATIC_LRU mutex.
+ */
PgHdr *pNextHash, *pPrevHash; /* Hash collision chain for PgHdr.pgno */
PgHdr *pNext, *pPrev; /* List of clean or dirty pages */
PgHdr *pNextLru, *pPrevLru; /* Part of global LRU list */
- int nRef; /* Number of users of this page */
- void *apSave[2]; /* Journal entries for in-memory databases */
};
/* Bit values for PgHdr.flags */
diff --git a/src/test_func.c b/src/test_func.c
index 2812382816..20f3307185 100644
--- a/src/test_func.c
+++ b/src/test_func.c
@@ -12,7 +12,7 @@
** Code for testing all sorts of SQLite interfaces. This code
** implements new SQL functions used by the test scripts.
**
-** $Id: test_func.c,v 1.12 2008/08/27 15:21:35 drh Exp $
+** $Id: test_func.c,v 1.13 2008/08/28 02:26:07 drh Exp $
*/
#include "sqlite3.h"
#include "tcl.h"
@@ -217,10 +217,7 @@ static void counterFunc(
int nArg, /* Number of function arguments */
sqlite3_value **argv /* Values for all function arguments */
){
- int i;
- int *pCounter;
-
- pCounter = (int*)sqlite3_get_auxdata(pCtx, 0);
+ int *pCounter = (int*)sqlite3_get_auxdata(pCtx, 0);
if( pCounter==0 ){
pCounter = sqlite3_malloc( sizeof(*pCounter) );
if( pCounter==0 ){