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Change the Pager.hasBeenUsed flag into Pager.hasHeldSharedLock in order to

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take it off the critical path in sqlite3PagerAcquire().

FossilOrigin-Name: b79096be7cb02aae2f303db33a8bf19e69204374
This commit is contained in:
drh
2015-09-03 17:54:32 +00:00
parent 076e85f59c
commit c98a4cc8b6
3 changed files with 13 additions and 12 deletions
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12
manifest
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@@ -1,5 +1,5 @@
C Add\sthe\ssqlite3VdbeLoadString()\sand\ssqlite3VdbeMultiLoad()\sroutines\sto\shelp\nwith\scode\sgeneration,\sespecially\son\sPRAGMAs.\s\sRename\ssqlite3VdbeAddGoto()\nto\sjust\ssqlite3VdbeGoto(). C Change\sthe\sPager.hasBeenUsed\sflag\sinto\sPager.hasHeldSharedLock\sin\sorder\sto\ntake\sit\soff\sthe\scritical\spath\sin\ssqlite3PagerAcquire().
D 2015-09-03T13:46:12.406 D 2015-09-03T17:54:32.014
F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
F Makefile.in f85066ce844a28b671aaeeff320921cd0ce36239 F Makefile.in f85066ce844a28b671aaeeff320921cd0ce36239
F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -324,7 +324,7 @@ F src/os_setup.h c9d4553b5aaa6f73391448b265b89bed0b890faa
F src/os_unix.c 76f493ed71c4154338049dee1bf6e47f69c74a55 F src/os_unix.c 76f493ed71c4154338049dee1bf6e47f69c74a55
F src/os_win.c 40b3af7a47eb1107d0d69e592bec345a3b7b798a F src/os_win.c 40b3af7a47eb1107d0d69e592bec345a3b7b798a
F src/os_win.h eb7a47aa17b26b77eb97e4823f20a00b8bda12ca F src/os_win.h eb7a47aa17b26b77eb97e4823f20a00b8bda12ca
F src/pager.c aa916ca28606ccf4b6877dfc2b643ccbca86589f F src/pager.c 2a9d77ac483a684c4187ec9ca786b551d3adfda5
F src/pager.h 6d435f563b3f7fcae4b84433b76a6ac2730036e2 F src/pager.h 6d435f563b3f7fcae4b84433b76a6ac2730036e2
F src/parse.y f599aa5e871a493330d567ced93de696f61f48f7 F src/parse.y f599aa5e871a493330d567ced93de696f61f48f7
F src/pcache.c cde06aa50962595e412d497e22fd2e07878ba1f0 F src/pcache.c cde06aa50962595e412d497e22fd2e07878ba1f0
@@ -1380,7 +1380,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
P d7f4bdf594e93c848f46901637861c8eed4c34df P 847387ec8e6fef283899578fb232b2c23b00ee5b
R 87d27a58ce6d4a6cd03f169f2370f2fe R 530c1d1d05feba269ca8969115207173
U drh U drh
Z bdbaccc5e83ea81c60c1b2c883af5b3e Z e28985417ac4a7094ed6187f7e395585

2
manifest.uuid
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@@ -1 +1 @@
847387ec8e6fef283899578fb232b2c23b00ee5b b79096be7cb02aae2f303db33a8bf19e69204374

11
src/pager.c
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@@ -647,7 +647,7 @@ struct Pager {
u8 doNotSpill; /* Do not spill the cache when non-zero */ u8 doNotSpill; /* Do not spill the cache when non-zero */
u8 subjInMemory; /* True to use in-memory sub-journals */ u8 subjInMemory; /* True to use in-memory sub-journals */
u8 bUseFetch; /* True to use xFetch() */ u8 bUseFetch; /* True to use xFetch() */
u8 hasBeenUsed; /* True if any content previously read */ u8 hasHeldSharedLock; /* True if a shared lock has ever been held */
Pgno dbSize; /* Number of pages in the database */ Pgno dbSize; /* Number of pages in the database */
Pgno dbOrigSize; /* dbSize before the current transaction */ Pgno dbOrigSize; /* dbSize before the current transaction */
Pgno dbFileSize; /* Number of pages in the database file */ Pgno dbFileSize; /* Number of pages in the database file */
@@ -5097,10 +5097,10 @@ int sqlite3PagerSharedLock(Pager *pPager){
); );
} }
if( !pPager->tempFile && pPager->hasBeenUsed ){ if( !pPager->tempFile && pPager->hasHeldSharedLock ){
/* The shared-lock has just been acquired then check to /* The shared-lock has just been acquired then check to
** see if the database has been modified. If the database has changed, ** see if the database has been modified. If the database has changed,
** flush the cache. The pPager->hasBeenUsed flag prevents this from ** flush the cache. The hasHeldSharedLock flag prevents this from
** occurring on the very first access to a file, in order to save a ** occurring on the very first access to a file, in order to save a
** single unnecessary sqlite3OsRead() call at the start-up. ** single unnecessary sqlite3OsRead() call at the start-up.
** **
@@ -5170,6 +5170,7 @@ int sqlite3PagerSharedLock(Pager *pPager){
assert( pPager->eState==PAGER_OPEN ); assert( pPager->eState==PAGER_OPEN );
}else{ }else{
pPager->eState = PAGER_READER; pPager->eState = PAGER_READER;
pPager->hasHeldSharedLock = 1;
} }
return rc; return rc;
} }
@@ -5267,7 +5268,7 @@ int sqlite3PagerAcquire(
if( pgno==0 ){ if( pgno==0 ){
return SQLITE_CORRUPT_BKPT; return SQLITE_CORRUPT_BKPT;
} }
pPager->hasBeenUsed = 1; assert( pPager->hasHeldSharedLock==1 );
/* If the pager is in the error state, return an error immediately. /* If the pager is in the error state, return an error immediately.
** Otherwise, request the page from the PCache layer. */ ** Otherwise, request the page from the PCache layer. */
@@ -5422,7 +5423,7 @@ DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
assert( pgno!=0 ); assert( pgno!=0 );
assert( pPager->pPCache!=0 ); assert( pPager->pPCache!=0 );
pPage = sqlite3PcacheFetch(pPager->pPCache, pgno, 0); pPage = sqlite3PcacheFetch(pPager->pPCache, pgno, 0);
assert( pPage==0 || pPager->hasBeenUsed ); assert( pPage==0 || pPager->hasHeldSharedLock );
if( pPage==0 ) return 0; if( pPage==0 ) return 0;
return sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pPage); return sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pPage);
} }