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Speed up xAccess() calls made on an RBU VFS when there are lots of open

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connections.

FossilOrigin-Name: 310b4b65b8c8ee080760c7efb4c7e20244c6063a5dba37a4f40490105aafd29f
This commit is contained in:
dan 2018-10-01 17:33:35 +00:00
parent 44d068532e
commit 49f84ce1cd
3 changed files with 82 additions and 34 deletions
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100
ext/rbu/sqlite3rbu.c
View File

@ -405,7 +405,8 @@ struct rbu_vfs {
sqlite3_vfs *pRealVfs; /* Underlying VFS */
sqlite3_mutex *mutex; /* Mutex to protect pMain */
sqlite3rbu *pRbu; /* Owner RBU object */
rbu_file *pMain; /* Linked list of main db files */
rbu_file *pMain; /* List of main db files */
rbu_file *pMainRbu; /* List of main db files with pRbu!=0 */
};
/*
@ -434,6 +435,7 @@ struct rbu_file {
const char *zWal; /* Wal filename for this main db file */
rbu_file *pWalFd; /* Wal file descriptor for this main db */
rbu_file *pMainNext; /* Next MAIN_DB file */
rbu_file *pMainRbuNext; /* Next MAIN_DB file with pRbu!=0 */
};
/*
@ -4030,6 +4032,69 @@ static int rbuUpdateTempSize(rbu_file *pFd, sqlite3_int64 nNew){
return SQLITE_OK;
}
/*
** Add an item to the main-db lists, if it is not already present.
**
** There are two main-db lists. One for all file descriptors, and one
** for all file descriptors with rbu_file.pDb!=0. If the argument has
** rbu_file.pDb!=0, then it is assumed to already be present on the
** main list and is only added to the pDb!=0 list.
*/
static void rbuMainlistAdd(rbu_file *p){
rbu_vfs *pRbuVfs = p->pRbuVfs;
rbu_file *pIter;
assert( (p->openFlags & SQLITE_OPEN_MAIN_DB) );
sqlite3_mutex_enter(pRbuVfs->mutex);
if( p->pRbu==0 ){
for(pIter=pRbuVfs->pMain; pIter; pIter=pIter->pMainNext);
p->pMainNext = pRbuVfs->pMain;
pRbuVfs->pMain = p;
}else{
for(pIter=pRbuVfs->pMainRbu; pIter && pIter!=p; pIter=pIter->pMainRbuNext){}
if( pIter==0 ){
p->pMainRbuNext = pRbuVfs->pMainRbu;
pRbuVfs->pMainRbu = p;
}
}
sqlite3_mutex_leave(pRbuVfs->mutex);
}
/*
** Remove an item from the main-db lists.
*/
static void rbuMainlistRemove(rbu_file *p){
rbu_file **pp;
sqlite3_mutex_enter(p->pRbuVfs->mutex);
for(pp=&p->pRbuVfs->pMain; *pp && *pp!=p; pp=&((*pp)->pMainNext)){}
if( *pp ) *pp = p->pMainNext;
p->pMainNext = 0;
for(pp=&p->pRbuVfs->pMainRbu; *pp && *pp!=p; pp=&((*pp)->pMainRbuNext)){}
if( *pp ) *pp = p->pMainRbuNext;
p->pMainRbuNext = 0;
sqlite3_mutex_leave(p->pRbuVfs->mutex);
}
/*
** Given that zWal points to a buffer containing a wal file name passed to
** either the xOpen() or xAccess() VFS method, search the main-db list for
** a file-handle opened by the same database connection on the corresponding
** database file.
**
** If parameter bRbu is true, only search for file-descriptors with
** rbu_file.pDb!=0.
*/
static rbu_file *rbuFindMaindb(rbu_vfs *pRbuVfs, const char *zWal, int bRbu){
rbu_file *pDb;
sqlite3_mutex_enter(pRbuVfs->mutex);
if( bRbu ){
for(pDb=pRbuVfs->pMainRbu; pDb && pDb->zWal!=zWal; pDb=pDb->pMainRbuNext){}
}else{
for(pDb=pRbuVfs->pMain; pDb && pDb->zWal!=zWal; pDb=pDb->pMainNext){}
}
sqlite3_mutex_leave(pRbuVfs->mutex);
return pDb;
}
/*
** Close an rbu file.
*/
@ -4047,17 +4112,14 @@ static int rbuVfsClose(sqlite3_file *pFile){
sqlite3_free(p->zDel);
if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
rbu_file **pp;
sqlite3_mutex_enter(p->pRbuVfs->mutex);
for(pp=&p->pRbuVfs->pMain; *pp!=p; pp=&((*pp)->pMainNext));
*pp = p->pMainNext;
sqlite3_mutex_leave(p->pRbuVfs->mutex);
rbuMainlistRemove(p);
rbuUnlockShm(p);
p->pReal->pMethods->xShmUnmap(p->pReal, 0);
}
else if( (p->openFlags & SQLITE_OPEN_DELETEONCLOSE) && p->pRbu ){
rbuUpdateTempSize(p, 0);
}
assert( p->pMainNext==0 && p->pRbuVfs->pMain!=p );
/* Close the underlying file handle */
rc = p->pReal->pMethods->xClose(p->pReal);
@ -4316,6 +4378,9 @@ static int rbuVfsFileControl(sqlite3_file *pFile, int op, void *pArg){
}else if( rc==SQLITE_NOTFOUND ){
pRbu->pTargetFd = p;
p->pRbu = pRbu;
if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
rbuMainlistAdd(p);
}
if( p->pWalFd ) p->pWalFd->pRbu = pRbu;
rc = SQLITE_OK;
}
@ -4477,20 +4542,6 @@ static int rbuVfsShmUnmap(sqlite3_file *pFile, int delFlag){
return rc;
}
/*
** Given that zWal points to a buffer containing a wal file name passed to
** either the xOpen() or xAccess() VFS method, return a pointer to the
** file-handle opened by the same database connection on the corresponding
** database file.
*/
static rbu_file *rbuFindMaindb(rbu_vfs *pRbuVfs, const char *zWal){
rbu_file *pDb;
sqlite3_mutex_enter(pRbuVfs->mutex);
for(pDb=pRbuVfs->pMain; pDb && pDb->zWal!=zWal; pDb=pDb->pMainNext){}
sqlite3_mutex_leave(pRbuVfs->mutex);
return pDb;
}
/*
** A main database named zName has just been opened. The following
** function returns a pointer to a buffer owned by SQLite that contains
@ -4569,7 +4620,7 @@ static int rbuVfsOpen(
pFd->zWal = rbuMainToWal(zName, flags);
}
else if( flags & SQLITE_OPEN_WAL ){
rbu_file *pDb = rbuFindMaindb(pRbuVfs, zName);
rbu_file *pDb = rbuFindMaindb(pRbuVfs, zName, 0);
if( pDb ){
if( pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
/* This call is to open a *-wal file. Intead, open the *-oal. This
@ -4621,10 +4672,7 @@ static int rbuVfsOpen(
** mutex protected linked list of all such files. */
pFile->pMethods = &rbuvfs_io_methods;
if( flags & SQLITE_OPEN_MAIN_DB ){
sqlite3_mutex_enter(pRbuVfs->mutex);
pFd->pMainNext = pRbuVfs->pMain;
pRbuVfs->pMain = pFd;
sqlite3_mutex_leave(pRbuVfs->mutex);
rbuMainlistAdd(pFd);
}
}else{
sqlite3_free(pFd->zDel);
@ -4672,7 +4720,7 @@ static int rbuVfsAccess(
** file opened instead.
*/
if( rc==SQLITE_OK && flags==SQLITE_ACCESS_EXISTS ){
rbu_file *pDb = rbuFindMaindb(pRbuVfs, zPath);
rbu_file *pDb = rbuFindMaindb(pRbuVfs, zPath, 1);
if( pDb && pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
if( *pResOut ){
rc = SQLITE_CANTOPEN;

14
manifest
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@ -1,5 +1,5 @@
C Fix\sa\spotential\scrash\sthat\scan\soccur\swhile\sreading\san\sindex\sfrom\sa\scorrupt\ndatabase\sfile.\s\sThe\scorruption\sis\sa\srecord-header-size\sthat\sis\slarger\sthan\n0x7fffffff.\s\sProblem\sdetected\sby\sOSSFuzz\sagainst\sGDAL\sand\sreported\sto\sus\s\n(with\sa\ssuggested\sfix)\sby\sEven\sRouault.\s\sThe\stest\scase\sis\sin\sTH3.
D 2018-10-01T13:54:30.911
C Speed\sup\sxAccess()\scalls\smade\son\san\sRBU\sVFS\swhen\sthere\sare\slots\sof\sopen\nconnections.
D 2018-10-01T17:33:35.846
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F Makefile.in 01e95208a78b57d056131382c493c963518f36da4c42b12a97eb324401b3a334
@ -348,7 +348,7 @@ F ext/rbu/rbusplit.test 69271c790732b28bd465551d80b0a9a3f074e189896ee8490ce56d22
F ext/rbu/rbutemplimit.test cd553a9288d515d0b5f87d277e76fd18c4aa740b761e7880fab11ce986ea18d1
F ext/rbu/rbuvacuum.test ff357e9b556ca7ad4673da0ff7f244def919ff858e0f9f350d3e30fdd83a62a8
F ext/rbu/rbuvacuum2.test 2074ab14fe66e1c7e7210c62562650dcd215bbaa
F ext/rbu/sqlite3rbu.c f438fea899d15d13ff3e3133242b9e378c37b5a3d76add8c342c68bdd65c6819
F ext/rbu/sqlite3rbu.c 71f8c09948d09ec9c5a8dbe7127e8ef61ef0853e698b2650be2485ac7b9c75c8
F ext/rbu/sqlite3rbu.h b42bcd4d8357268c6c39ab2a60b29c091e89328fa8cc49c8fac5ab8d007e79b2
F ext/rbu/test_rbu.c baa23eb28457580673d2175e5f0c29ced0cd320ee819b13ad362398c53b96e90
F ext/repair/README.md 92f5e8aae749a4dae14f02eea8e1bb42d4db2b6ce5e83dbcdd6b1446997e0c15
@ -1770,7 +1770,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
P c52f457e56eb9d573eb67093731eb231aaf6fd6dbdc397e6f948b82736fbe3ab
R c75c41f8def35162ce620ba59792b15c
U drh
Z 2db3890d5903ac5d614f7b18f951a8a9
P 8ac2cdda68f92b0352bc7f0b4be5fca4bb58565ca65055fb34153cc284ed6922
R a63f057a754c642de8f2617ecd7043d5
U dan
Z c6e86f7777ba1872e2992f69103701bb

2
manifest.uuid
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@ -1 +1 @@
8ac2cdda68f92b0352bc7f0b4be5fca4bb58565ca65055fb34153cc284ed6922
310b4b65b8c8ee080760c7efb4c7e20244c6063a5dba37a4f40490105aafd29f