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Overview
| Comment: | Avoid locking shm-lock WAL_READ_LOCK(0) during recovery. Doing this allows recovery to proceed while a readonly_shm connection in unlocked mode has an ongoing read transaction. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | readonly-wal-recovery |
| Files: | files | file ages | folders |
| SHA3-256: |
5190d84a296b7cf716ef43bf7b6d4d35 |
| User & Date: | dan 2017-11-02 11:12:03 |
Context
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2017-11-02
| ||
| 18:57 | Fix test cases in wal2.test broken by the locking change in the previous commit. check-in: f569c351 user: dan tags: readonly-wal-recovery | |
| 11:12 | Avoid locking shm-lock WAL_READ_LOCK(0) during recovery. Doing this allows recovery to proceed while a readonly_shm connection in unlocked mode has an ongoing read transaction. check-in: 5190d84a user: dan tags: readonly-wal-recovery | |
|
2017-11-01
| ||
| 20:59 | If a readonly_shm connection cannot map the *-shm file because no other process is holding the DMS lock, have it read from the database file only, ignoring any content in the wal file. check-in: ce5d13c2 user: dan tags: readonly-wal-recovery | |
Changes
Changes to src/wal.c.
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** the necessary locks, this routine returns SQLITE_BUSY.
*/
static int walIndexRecover(Wal *pWal){
int rc; /* Return Code */
i64 nSize; /* Size of log file */
u32 aFrameCksum[2] = {0, 0};
int iLock; /* Lock offset to lock for checkpoint */
int nLock; /* Number of locks to hold */
/* Obtain an exclusive lock on all byte in the locking range not already
** locked by the caller. The caller is guaranteed to have locked the
** WAL_WRITE_LOCK byte, and may have also locked the WAL_CKPT_LOCK byte.
** If successful, the same bytes that are locked here are unlocked before
** this function returns.
*/
assert( pWal->ckptLock==1 || pWal->ckptLock==0 );
assert( WAL_ALL_BUT_WRITE==WAL_WRITE_LOCK+1 );
assert( WAL_CKPT_LOCK==WAL_ALL_BUT_WRITE );
assert( pWal->writeLock );
iLock = WAL_ALL_BUT_WRITE + pWal->ckptLock;
nLock = SQLITE_SHM_NLOCK - iLock;
rc = walLockExclusive(pWal, iLock, nLock);
if( rc ){
return rc;
}
WALTRACE(("WAL%p: recovery begin...\n", pWal));
memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
rc = sqlite3OsFileSize(pWal->pWalFd, &nSize);
if( rc!=SQLITE_OK ){
goto recovery_error;
................................................................................
pWal->hdr.mxFrame, pWal->zWalName
);
}
}
recovery_error:
WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
walUnlockExclusive(pWal, iLock, nLock);
return rc;
}
/*
** Close an open wal-index.
*/
static void walIndexClose(Wal *pWal, int isDelete){
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** the necessary locks, this routine returns SQLITE_BUSY.
*/
static int walIndexRecover(Wal *pWal){
int rc; /* Return Code */
i64 nSize; /* Size of log file */
u32 aFrameCksum[2] = {0, 0};
int iLock; /* Lock offset to lock for checkpoint */
/* Obtain an exclusive lock on all byte in the locking range not already
** locked by the caller. The caller is guaranteed to have locked the
** WAL_WRITE_LOCK byte, and may have also locked the WAL_CKPT_LOCK byte.
** If successful, the same bytes that are locked here are unlocked before
** this function returns.
*/
assert( pWal->ckptLock==1 || pWal->ckptLock==0 );
assert( WAL_ALL_BUT_WRITE==WAL_WRITE_LOCK+1 );
assert( WAL_CKPT_LOCK==WAL_ALL_BUT_WRITE );
assert( pWal->writeLock );
iLock = WAL_ALL_BUT_WRITE + pWal->ckptLock;
rc = walLockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
if( rc==SQLITE_OK ){
rc = walLockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
if( rc!=SQLITE_OK ){
walUnlockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
}
}
if( rc ){
return rc;
}
WALTRACE(("WAL%p: recovery begin...\n", pWal));
memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
rc = sqlite3OsFileSize(pWal->pWalFd, &nSize);
if( rc!=SQLITE_OK ){
goto recovery_error;
................................................................................
pWal->hdr.mxFrame, pWal->zWalName
);
}
}
recovery_error:
WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
walUnlockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
return rc;
}
/*
** Close an open wal-index.
*/
static void walIndexClose(Wal *pWal, int isDelete){
|
Changes to test/walro2.test.
77 78 79 80 81 82 83 84 85 86 87 |
code3 { sqlite3 db3 test.db2 }
sql3 { SELECT * FROM t1 }
} {a b c d}
do_test 1.3.2 {
sql1 { SELECT * FROM t1 }
} {a b c d}
}
finish_test
|
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > |
77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 |
code3 { sqlite3 db3 test.db2 }
sql3 { SELECT * FROM t1 }
} {a b c d}
do_test 1.3.2 {
sql1 { SELECT * FROM t1 }
} {a b c d}
code1 { db close }
code2 { db2 close }
code3 { db3 close }
do_test 2.1 {
code2 { sqlite3 db2 test.db }
sql2 {
INSERT INTO t1 VALUES('e', 'f');
INSERT INTO t1 VALUES('g', 'h');
}
file exists test.db-shm
} {1}
do_test 2.2 {
forcecopy test.db test.db2
forcecopy test.db-wal test.db2-wal
forcecopy test.db-shm test.db2-shm
code1 {
sqlite3 db file:test.db2?readonly_shm=1
}
sql1 {
BEGIN;
SELECT * FROM t1;
}
} {a b c d}
do_test 2.3.1 {
code3 { sqlite3 db3 test.db2 }
sql3 { SELECT * FROM t1 }
} {a b c d e f g h}
}
finish_test
|