From: dan Date: Sat, 29 Aug 2020 15:36:34 +0000 (+0000) Subject: Improve performance of wal-mode locking on unix in cases where there are hundreds... X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c262c979106aaeef765657dfd3b3934797992492;p=thirdparty%2Fsqlite.git Improve performance of wal-mode locking on unix in cases where there are hundreds of connections to a single database within the same process. FossilOrigin-Name: 30214727f7af9b5471654b0dd2cd234f0e284b24661104e55a9be771baf9577a --- diff --git a/manifest b/manifest index 7aed114cc7..dc68a99711 100644 --- a/manifest +++ b/manifest @@ -1,5 +1,5 @@ -C Update\sthis\sbranch\swith\slatest\sfrom\sbegin-concurrent-pnu. -D 2020-08-11T14:06:38.086 +C Improve\sperformance\sof\swal-mode\slocking\son\sunix\sin\scases\swhere\sthere\sare\shundreds\sof\sconnections\sto\sa\ssingle\sdatabase\swithin\sthe\ssame\sprocess. +D 2020-08-29T15:36:34.942 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724 @@ -525,7 +525,7 @@ F src/os.c 80e4cf3e5da06be03ca641661e331ce60eeeeabf0d7354dbb1c0e166d0eedbbe F src/os.h 48388821692e87da174ea198bf96b1b2d9d83be5dfc908f673ee21fafbe0d432 F src/os_common.h b2f4707a603e36811d9b1a13278bffd757857b85 F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586 -F src/os_unix.c c79bf7138f5c760bcf167065f08ca1c23f27fe06d8a4ad57432099e966823fe9 +F src/os_unix.c 6315625481f2f2e65a33324730ad94357818c84a00c4459728e00d9cc82c81b9 F src/os_win.c a2149ff0a85c1c3f9cc102a46c673ce87e992396ba3411bfb53db66813b32f1d F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a F src/pager.c 6da497a9d6071d09c5b7d4ae8c5c022a89a625e286d03cc2e1589025cb9a3c07 @@ -1896,7 +1896,11 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0 -P e39e7a6fc793912ab26e5ffc746b38941ec69a7edc100a6034d3ffb1edb606a7 2ae78c993e6a4ffd9ac1c8aaadf4976eacb5486e23c228988e9d3f379ed801c3 -R 791a5872c711641c9ab31256451cd74d +P 3ee73880ed280f33d554269d4e964cce0c44b5c6c43937da4e547c39f16e860b +Q +a1c19eea8f141b89a0921da0724096feb21a772ef6654f164e2c36ebf9f7871e +R 0749a7fd76499ea288e0497f2ffe422d +T *branch * begin-concurrent-unixshmlock-opt +T *sym-begin-concurrent-unixshmlock-opt * +T -sym-begin-concurrent-report * U dan -Z 8cc894655403c6a78b14825962271a49 +Z b30e9f5758699ae064eede4bc7397127 diff --git a/manifest.uuid b/manifest.uuid index f0fcd4695f..47010edd40 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -3ee73880ed280f33d554269d4e964cce0c44b5c6c43937da4e547c39f16e860b \ No newline at end of file +30214727f7af9b5471654b0dd2cd234f0e284b24661104e55a9be771baf9577a \ No newline at end of file diff --git a/src/os_unix.c b/src/os_unix.c index 808d7fc7a7..c1195db9d3 100644 --- a/src/os_unix.c +++ b/src/os_unix.c @@ -4276,6 +4276,7 @@ struct unixShmNode { char **apRegion; /* Array of mapped shared-memory regions */ int nRef; /* Number of unixShm objects pointing to this */ unixShm *pFirst; /* All unixShm objects pointing to this */ + int aLock[SQLITE_SHM_NLOCK]; /* # shared locks on slot, -1==excl lock */ #ifdef SQLITE_DEBUG u8 exclMask; /* Mask of exclusive locks held */ u8 sharedMask; /* Mask of shared locks held */ @@ -4816,6 +4817,38 @@ shmpage_out: return rc; } +/* +** Check that the pShmNode->aLock[] array comports with the locking bitmasks +** held by each client. Return true if it does, or false otherwise. This +** is to be used in an assert(). e.g. +** +** assert( assertLockingArrayOk(pShmNode) ); +*/ +#ifdef SQLITE_DEBUG +static int assertLockingArrayOk(unixShmNode *pShmNode){ + unixShm *pX; + int aLock[SQLITE_SHM_NLOCK]; + assert( sqlite3_mutex_held(pShmNode->pShmMutex) ); + + memset(aLock, 0, sizeof(aLock)); + for(pX=pShmNode->pFirst; pX; pX=pX->pNext){ + int i; + for(i=0; iexclMask & (1<sharedMask & (1<=0 ); + aLock[i]++; + } + } + } + + assert( 0==memcmp(pShmNode->aLock, aLock, sizeof(aLock)) ); + return (memcmp(pShmNode->aLock, aLock, sizeof(aLock))==0); +} +#endif + /* ** Change the lock state for a shared-memory segment. ** @@ -4832,10 +4865,10 @@ static int unixShmLock( ){ unixFile *pDbFd = (unixFile*)fd; /* Connection holding shared memory */ unixShm *p = pDbFd->pShm; /* The shared memory being locked */ - unixShm *pX; /* For looping over all siblings */ unixShmNode *pShmNode = p->pShmNode; /* The underlying file iNode */ int rc = SQLITE_OK; /* Result code */ u16 mask; /* Mask of locks to take or release */ + int *aLock = pShmNode->aLock; assert( pShmNode==pDbFd->pInode->pShmNode ); assert( pShmNode->pInode==pDbFd->pInode ); @@ -4874,78 +4907,76 @@ static int unixShmLock( mask = (1<<(ofst+n)) - (1<1 || mask==(1<pShmMutex); + assert( assertLockingArrayOk(pShmNode) ); if( flags & SQLITE_SHM_UNLOCK ){ - u16 allMask = 0; /* Mask of locks held by siblings */ + if( (p->exclMask|p->sharedMask) & mask ){ + int ii; + int bUnlock = 1; - /* See if any siblings hold this same lock */ - for(pX=pShmNode->pFirst; pX; pX=pX->pNext){ - if( pX==p ) continue; - assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 ); - allMask |= pX->sharedMask; - } + for(ii=ofst; ii((p->sharedMask & (1<sharedMask & (1<1 ); + aLock[ofst]--; + } - /* Undo the local locks */ - if( rc==SQLITE_OK ){ - p->exclMask &= ~mask; - p->sharedMask &= ~mask; - } + /* Undo the local locks */ + if( rc==SQLITE_OK ){ + p->exclMask &= ~mask; + p->sharedMask &= ~mask; + } + } }else if( flags & SQLITE_SHM_SHARED ){ - u16 allShared = 0; /* Union of locks held by connections other than "p" */ - - /* Find out which shared locks are already held by sibling connections. - ** If any sibling already holds an exclusive lock, go ahead and return - ** SQLITE_BUSY. - */ - for(pX=pShmNode->pFirst; pX; pX=pX->pNext){ - if( (pX->exclMask & mask)!=0 ){ + assert( n==1 ); + assert( (p->exclMask & (1<sharedMask & mask)==0 ){ + if( aLock[ofst]<0 ){ rc = SQLITE_BUSY; - break; - } - allShared |= pX->sharedMask; - } - - /* Get shared locks at the system level, if necessary */ - if( rc==SQLITE_OK ){ - if( (allShared & mask)==0 ){ + }else if( aLock[ofst]==0 ){ rc = unixShmSystemLock(pDbFd, F_RDLCK, ofst+UNIX_SHM_BASE, n); - }else{ - rc = SQLITE_OK; } - } - /* Get the local shared locks */ - if( rc==SQLITE_OK ){ - p->sharedMask |= mask; + /* Get the local shared locks */ + if( rc==SQLITE_OK ){ + p->sharedMask |= mask; + aLock[ofst]++; + } } }else{ /* Make sure no sibling connections hold locks that will block this - ** lock. If any do, return SQLITE_BUSY right away. - */ - for(pX=pShmNode->pFirst; pX; pX=pX->pNext){ - if( (pX->exclMask & mask)!=0 || (pX->sharedMask & mask)!=0 ){ + ** lock. If any do, return SQLITE_BUSY right away. */ + int ii; + for(ii=ofst; iisharedMask & mask)==0 ); + if( (p->exclMask & (1<sharedMask & mask)==0 ); p->exclMask |= mask; + for(ii=ofst; iipShmMutex); OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x\n", p->id, osGetpid(0), p->sharedMask, p->exclMask));