Speed improvements for in-memory databases by omitting flag clearing on pages

where it is impossible for the flag to be set and by avoiding assert()s on non-debugging builds. Ticket #3384. (CVS 5715) FossilOrigin-Name: a7fd9e622bc1050e78f227ec42b6ba90c87c865a
2025-08-08 14:02:16 +03:00 · 2008-09-17 20:06:26 +00:00
parent 89bae3ed7a
commit b3df2e1cfe
5 changed files with 51 additions and 47 deletions
--- a/18
+++ b/18
@@ -1,5 +1,5 @@
-C Changes\sto\stest\sscripts\sto\ssupport\srunning\son\ssymbian.\s(CVS\s5714)
-D 2008-09-17T16:14:10
+C Speed\simprovements\sfor\sin-memory\sdatabases\sby\somitting\sflag\sclearing\son\spages\nwhere\sit\sis\simpossible\sfor\sthe\sflag\sto\sbe\sset\sand\sby\savoiding\sassert()s\son\nnon-debugging\sbuilds.\s\sTicket\s#3384.\s(CVS\s5715)
+D 2008-09-17T20:06:26
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in d15a7ebfe5e057a72a49805ffb302dbb601c8329
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -137,11 +137,11 @@ F src/os_common.h 24525d8b7bce66c374dfc1810a6c9043f3359b60
 F src/os_os2.c e391fc95adc744bbdcefd4d11e3066998185a0a0
 F src/os_unix.c 8f4def6a92681735908fa1b87b5cc0291ebafde6
 F src/os_win.c 3209dc0ed734291764393ea8d534ba0d8696a540
-F src/pager.c f21654d1fcfd62ce058dbb88d07159745dc5bd84
+F src/pager.c 34318b85cead25e179a6ff83092c79d6dcecb2fd
 F src/pager.h c45380ca9d0933ea5bc4ecb3a43958b6d2ec5a9c
 F src/parse.y d0f76d2cb8d6883d5600dc20beb961a6022b94b8
-F src/pcache.c a39908e73cf5001dec2cc7a55a477fe8e8611db9
-F src/pcache.h 53730c33310cdf7a5c94e8333c853d59a3b30226
+F src/pcache.c c799d753a5d4b913961a4fe66c8a7c706b04d28d
+F src/pcache.h deddea69babf3e0931b11eea3bf5c9e33a654389
 F src/pragma.c e633b6b7dabc110e2abfed4e35ba34a4039cb65c
 F src/prepare.c c7e00ed1b0bdcf699b1aad651247d4dc3d281b0b
 F src/printf.c 785f87120589c1db672e37c6eb1087c456e6f84d
@@ -637,7 +637,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 1dbced29de5f59ba2ebf877edcadf171540374d1
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 94fde77b9a4efde5f7fb2a84fedaf38b0ebbac70
-R 5cb1f4f412c11fd992c399fc6668cf38
-U danielk1977
-Z f12860bdb96f15ad02a57af76d19c3b1
+P 6ef34e9d3118965781c69011deaede1ebbb19b12
+R a27713f2ccd1c6c2e7e56fb7534b72ec
+U drh
+Z ee142ff5e27b59538a7c71659e26324f
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-6ef34e9d3118965781c69011deaede1ebbb19b12
+a7fd9e622bc1050e78f227ec42b6ba90c87c865a
--- 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 1.490 2008/09/16 05:12:24 danielk1977 Exp $
+** @(#) $Id: pager.c,v 1.491 2008/09/17 20:06:26 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -994,8 +994,8 @@ static int pager_end_transaction(Pager *pPager, int hasMaster){
 #ifdef SQLITE_CHECK_PAGES
    sqlite3PcacheIterate(pPager->pPCache, pager_set_pagehash);
 #endif
-    sqlite3PcacheSetFlags(pPager->pPCache,
-       ~(PGHDR_IN_JOURNAL | PGHDR_NEED_SYNC), 0
+    sqlite3PcacheClearFlags(pPager->pPCache,
+       PGHDR_IN_JOURNAL | PGHDR_NEED_SYNC
    );
    pPager->dirtyCache = 0;
    pPager->nRec = 0;
@@ -1663,7 +1663,7 @@ void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
 */
 #ifndef SQLITE_OMIT_PAGER_PRAGMAS
 void sqlite3PagerSetSafetyLevel(Pager *pPager, int level, int bFullFsync){
-  pPager->noSync =  level==1 || pPager->tempFile;
+  pPager->noSync =  level==1 || pPager->tempFile || MEMDB;
  pPager->fullSync = level==3 && !pPager->tempFile;
  pPager->sync_flags = (bFullFsync?SQLITE_SYNC_FULL:SQLITE_SYNC_NORMAL);
  if( pPager->noSync ) pPager->needSync = 0;
@@ -1761,6 +1761,7 @@ int sqlite3PagerOpen(
    if( strcmp(zFilename,":memory:")==0 ){
      memDb = 1;
      zPathname[0] = 0;
+      useJournal = 0;
    }else
 #endif
    {
@@ -1885,7 +1886,7 @@ int sqlite3PagerOpen(
  }

  /* pPager->journalOpen = 0; */
-  pPager->useJournal = useJournal && !memDb;
+  pPager->useJournal = useJournal;
  pPager->noReadlock = noReadlock && readOnly;
  /* pPager->stmtOpen = 0; */
  /* pPager->stmtInUse = 0; */
@@ -2322,8 +2323,7 @@ static int syncJournal(Pager *pPager){

    /* Erase the needSync flag from every page.
    */
-    sqlite3PcacheSetFlags(pPager->pPCache, ~PGHDR_NEED_SYNC, 0);
-    /* lruListSetFirstSynced(pPager); */
+    sqlite3PcacheClearFlags(pPager->pPCache, PGHDR_NEED_SYNC);
  }

 #ifndef NDEBUG
@@ -2333,7 +2333,6 @@ static int syncJournal(Pager *pPager){
  */
  else{
    sqlite3PcacheAssertFlags(pPager->pPCache, 0, PGHDR_NEED_SYNC);
-    /* assert( pPager->lru.pFirstSynced==pPager->lru.pFirst ); */
  }
 #endif

@@ -2411,11 +2410,9 @@ static int pager_write_pagelist(PgHdr *pList){
 #ifdef SQLITE_CHECK_PAGES
    pList->pageHash = pager_pagehash(pList);
 #endif
-    /* makeClean(pList); */
    pList = pList->pDirty;
  }

-  /* sqlite3PcacheCleanAll(pPager->pPCache); */
  return SQLITE_OK;
 }

@@ -2845,6 +2842,7 @@ static int pagerAcquire(
    PAGER_INCR(pPager->nMiss);
    pPg->pPager = pPager;
    if( sqlite3BitvecTest(pPager->pInJournal, pgno) ){
+      assert( !MEMDB );
      pPg->flags |= PGHDR_IN_JOURNAL;
    }
    memset(pPg->pExtra, 0, pPager->nExtra);
@@ -3393,6 +3391,7 @@ int sqlite3PagerWrite(DbPage *pDbPage){
    ** before any of them can be written out to the database file.
    */
    if( needSync ){
+      assert( !MEMDB && pPager->noSync==0 );
      for(ii=0; ii<nPage && needSync; ii++){
        PgHdr *pPage = pager_lookup(pPager, pg1+ii);
        if( pPage ) pPage->flags |= PGHDR_NEED_SYNC;
@@ -3805,9 +3804,7 @@ int sqlite3PagerCommitPhaseTwo(Pager *pPager){
  if( MEMDB ){
    sqlite3PcacheCommit(pPager->pPCache, 0);
    sqlite3PcacheCleanAll(pPager->pPCache);
-    sqlite3PcacheSetFlags(pPager->pPCache, 
-       ~(PGHDR_IN_JOURNAL | PGHDR_NEED_SYNC), 0
-    );
+    sqlite3PcacheAssertFlags(pPager->pPCache, 0, PGHDR_IN_JOURNAL);
    pPager->state = PAGER_SHARED;
  }else{
    assert( pPager->state==PAGER_SYNCED || !pPager->dirtyCache );
@@ -3836,9 +3833,7 @@ int sqlite3PagerRollback(Pager *pPager){
    sqlite3PcacheRollback(pPager->pPCache, 1);
    sqlite3PcacheRollback(pPager->pPCache, 0);
    sqlite3PcacheCleanAll(pPager->pPCache);
-    sqlite3PcacheSetFlags(pPager->pPCache, 
-       ~(PGHDR_IN_JOURNAL | PGHDR_NEED_SYNC), 0
-    );
+    sqlite3PcacheAssertFlags(pPager->pPCache, 0, PGHDR_IN_JOURNAL);
    pPager->dbSize = pPager->origDbSize;
    pager_truncate_cache(pPager);
    pPager->stmtInUse = 0;
@@ -3976,7 +3971,6 @@ int sqlite3PagerStmtCommit(Pager *pPager){
  if( pPager->stmtInUse ){
    PAGERTRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
    if( !MEMDB ){
-      /* sqlite3OsTruncate(pPager->stfd, 0); */
      sqlite3BitvecDestroy(pPager->pInStmt);
      pPager->pInStmt = 0;
    }else{
@@ -4077,7 +4071,7 @@ void sqlite3PagerSetCodec(
 **
 ** There must be no references to the page previously located at
 ** pgno (which we call pPgOld) though that page is allowed to be
-** in cache.  If the page previous located at pgno is not already
+** in cache.  If the page previously located at pgno is not already
 ** in the rollback journal, it is not put there by by this routine.
 **
 ** References to the page pPg remain valid. Updating any
@@ -4132,6 +4126,7 @@ int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
    pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
  }
  if( sqlite3BitvecTest(pPager->pInJournal, pgno) ){
+    assert( !MEMDB );
    pPg->flags |= PGHDR_IN_JOURNAL;
  }

@@ -4174,6 +4169,7 @@ int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
      return rc;
    }
    pPager->needSync = 1;
+    assert( pPager->noSync==0 && !MEMDB );
    pPgHdr->flags |= PGHDR_NEED_SYNC;
    pPgHdr->flags |= PGHDR_IN_JOURNAL;
    makeDirty(pPgHdr);
--- a/src/pcache.c
+++ b/src/pcache.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** This file implements that page cache.
 **
-** @(#) $Id: pcache.c,v 1.28 2008/09/17 11:02:57 danielk1977 Exp $
+** @(#) $Id: pcache.c,v 1.29 2008/09/17 20:06:26 drh Exp $
 */
 #include "sqliteInt.h"

@@ -875,7 +875,6 @@ void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
  pcacheRemoveFromHash(p);
  p->pgno = newPgno;
  if( newPgno==0 ){
-    p->flags |= PGHDR_REUSE_UNLIKELY;
    pcacheFree(p->apSave[0]);
    pcacheFree(p->apSave[1]);
    p->apSave[0] = 0;
@@ -883,6 +882,7 @@ void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
    if( (p->flags & PGHDR_DIRTY) ){
      pcacheMakeClean(p);
    }
+    p->flags = PGHDR_REUSE_UNLIKELY;
  }
  pcacheAddToHash(p);
  pcacheExitMutex();
@@ -1004,12 +1004,14 @@ int sqlite3PcachePreserve(PgHdr *p, int idJournal){
 */
 void sqlite3PcacheCommit(PCache *pCache, int idJournal){
  PgHdr *p;
+  int mask = idJournal==0 ? ~PGHDR_IN_JOURNAL : 0xffffff;
  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;
    }
+    p->flags &= mask;
  }
  pcacheExitMutex();
 }
@@ -1020,6 +1022,7 @@ void sqlite3PcacheCommit(PCache *pCache, int idJournal){
 void sqlite3PcacheRollback(PCache *pCache, int idJournal){
  PgHdr *p;
  int sz;
+  int mask = idJournal==0 ? ~PGHDR_IN_JOURNAL : 0xffffff;
  pcacheEnterMutex();     /* Mutex is required to call pcacheFree() */
  sz = pCache->szPage;
  for(p=pCache->pDirty; p; p=p->pNext){
@@ -1028,10 +1031,12 @@ void sqlite3PcacheRollback(PCache *pCache, int idJournal){
      pcacheFree(p->apSave[idJournal]);
      p->apSave[idJournal] = 0;
    }
+    p->flags &= mask;
  }
  pcacheExitMutex();
 }

+#ifndef NDEBUG
 /* 
 ** Assert flags settings on all pages.  Debugging only.
 */
@@ -1046,6 +1051,7 @@ void sqlite3PcacheAssertFlags(PCache *pCache, int trueMask, int falseMask){
    assert( (p->flags&falseMask)==0 );
  }
 }
+#endif

 /* 
 ** Discard the contents of the cache.
@@ -1178,24 +1184,23 @@ void sqlite3PcacheIterate(PCache *pCache, void (*xIter)(PgHdr *)){
 /* 
 ** Set flags on all pages in the page cache 
 */
-void sqlite3PcacheSetFlags(PCache *pCache, int andMask, int orMask){
+void sqlite3PcacheClearFlags(PCache *pCache, int mask){
  PgHdr *p;

-  assert( (orMask&PGHDR_NEED_SYNC)==0 );
-
  /* Obtain the global mutex before modifying any PgHdr.flags variables 
  ** or traversing the LRU list.
  */ 
  pcacheEnterMutex();

+  mask = ~mask;
  for(p=pCache->pDirty; p; p=p->pNext){
-    p->flags = (p->flags&andMask)|orMask;
+    p->flags &= mask;
  }
  for(p=pCache->pClean; p; p=p->pNext){
-    p->flags = (p->flags&andMask)|orMask;
+    p->flags &= mask;
  }

-  if( 0==(andMask&PGHDR_NEED_SYNC) ){
+  if( 0==(mask&PGHDR_NEED_SYNC) ){
    pCache->pSynced = pCache->pDirtyTail;
    assert( !pCache->pSynced || (pCache->pSynced->flags&PGHDR_NEED_SYNC)==0 );
  }
--- 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 1.9 2008/08/29 09:10:03 danielk1977 Exp $
+** @(#) $Id: pcache.h,v 1.10 2008/09/17 20:06:26 drh Exp $
 */

 #ifndef _PCACHE_H_
@@ -53,13 +53,12 @@ struct PgHdr {

 /* Bit values for PgHdr.flags */
 #define PGHDR_IN_JOURNAL        0x001  /* Page is in rollback journal */
-#define PGHDR_IN_STMTJRNL       0x002  /* Page is in the statement journal */
-#define PGHDR_DIRTY             0x004  /* Page has changed */
-#define PGHDR_NEED_SYNC         0x008  /* Peed to fsync this page */
-#define PGHDR_NEED_READ         0x020  /* Content is unread */
-#define PGHDR_IS_INIT           0x040  /* pData is initialized */
-#define PGHDR_REUSE_UNLIKELY    0x080  /* Hint: Reuse is unlikely */
-#define PGHDR_DONT_WRITE        0x100  /* Do not write content to disk */
+#define PGHDR_DIRTY             0x002  /* Page has changed */
+#define PGHDR_NEED_SYNC         0x004  /* Fsync the rollback journal before
+                                       ** writing this page to the database */
+#define PGHDR_NEED_READ         0x008  /* Content is unread */
+#define PGHDR_REUSE_UNLIKELY    0x010  /* A hint that reuse is unlikely */
+#define PGHDR_DONT_WRITE        0x020  /* Do not write content to disk */

 /* Initialize and shutdown the page cache subsystem */
 int sqlite3PcacheInitialize(void);
@@ -122,11 +121,15 @@ PgHdr *sqlite3PcacheDirtyList(PCache*);
 /* Reset and close the cache object */
 void sqlite3PcacheClose(PCache*);

-/* Set flags on all pages in the page cache */
-void sqlite3PcacheSetFlags(PCache*, int andMask, int orMask);
+/* Clear flags from pages of the page cache */
+void sqlite3PcacheClearFlags(PCache*, int mask);

 /* Assert flags settings on all pages.  Debugging only */
-void sqlite3PcacheAssertFlags(PCache*, int trueMask, int falseMask);
+#ifndef NDEBUG
+  void sqlite3PcacheAssertFlags(PCache*, int trueMask, int falseMask);
+#else
+# define sqlite3PcacheAssertFlags(A,B,C)
+#endif

 /* Return true if the number of dirty pages is 0 or 1 */
 int sqlite3PcacheZeroOrOneDirtyPages(PCache*);