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Overview
| Comment: | Fix another problem involving unlocked transactions and wal-file restarts. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | begin-concurrent |
| Files: | files | file ages | folders |
| SHA1: |
4460764ea8fc948fe02f0a0947685783 |
| User & Date: | dan 2015-08-24 06:43:25 |
Context
|
2015-08-24
| ||
| 06:44 | Merge trunk changes with this branch. (check-in: 876810c2 user: dan tags: begin-concurrent) | |
| 06:43 | Fix another problem involving unlocked transactions and wal-file restarts. (check-in: 4460764e user: dan tags: begin-concurrent) | |
|
2015-08-22
| ||
| 20:32 | Fix a problem to do with detecting unlocked transaction conflicts if another client restarts the wal while the transaction is running. (check-in: e3968b25 user: dan tags: begin-concurrent) | |
Changes
Changes to src/pager.c.
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}
int sqlite3PagerUpgradeSnapshot(Pager *pPager, DbPage *pPage1){
int rc;
u32 iFrame = 0;
assert( pPager->pWal && pPager->pAllRead );
sqlite3WalUpgradeSnapshot(pPager->pWal);
rc = sqlite3WalFindFrame(pPager->pWal, 1, &iFrame);
if( rc==SQLITE_OK ){
rc = readDbPage(pPage1, iFrame);
}
return rc;
}
|
| > | > |
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}
int sqlite3PagerUpgradeSnapshot(Pager *pPager, DbPage *pPage1){
int rc;
u32 iFrame = 0;
assert( pPager->pWal && pPager->pAllRead );
rc = sqlite3WalUpgradeSnapshot(pPager->pWal);
if( rc==SQLITE_OK ){
rc = sqlite3WalFindFrame(pPager->pWal, 1, &iFrame);
}
if( rc==SQLITE_OK ){
rc = readDbPage(pPage1, iFrame);
}
return rc;
}
|
Changes to src/wal.c.
2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 .... 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 .... 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 |
}
}
}
return rc;
}
void sqlite3WalUpgradeSnapshot(Wal *pWal){
assert( pWal->writeLock );
memcpy(&pWal->hdr, (void*)walIndexHdr(pWal), sizeof(WalIndexHdr));
}
/*
** End a write transaction. The commit has already been done. This
** routine merely releases the lock.
*/
int sqlite3WalEndWriteTransaction(Wal *pWal){
................................................................................
**
** SQLITE_OK is returned if no error is encountered (regardless of whether
** or not pWal->hdr.mxFrame is modified). An SQLite error code is returned
** if an error occurs.
*/
static int walRestartLog(Wal *pWal){
int rc = SQLITE_OK;
int cnt;
if( pWal->readLock==0 ){
volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
assert( pInfo->nBackfill==pWal->hdr.mxFrame );
if( pInfo->nBackfill>0 ){
u32 salt1;
sqlite3_randomness(4, &salt1);
................................................................................
** to handle if this transaction is rolled back. */
walRestartHdr(pWal, salt1);
walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
}else if( rc!=SQLITE_BUSY ){
return rc;
}
}
walUnlockShared(pWal, WAL_READ_LOCK(0));
pWal->readLock = -1;
cnt = 0;
do{
int notUsed;
rc = walTryBeginRead(pWal, ¬Used, 1, ++cnt);
}while( rc==WAL_RETRY );
assert( (rc&0xff)!=SQLITE_BUSY ); /* BUSY not possible when useWal==1 */
testcase( (rc&0xff)==SQLITE_IOERR );
testcase( rc==SQLITE_PROTOCOL );
testcase( rc==SQLITE_OK );
}
return rc;
}
/*
** Information about the current state of the WAL file and where
** the next fsync should occur - passed from sqlite3WalFrames() into
|
> > > > > > > > > > > > > > > > > > > > > > > > > | > > > > > > > > > > < < > | | | | | | | | | < |
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}
}
}
return rc;
}
/*
** This function is called by a writer that has a read-lock on aReadmark[0]
** (pWal->readLock==0). This function relinquishes that lock and takes a
** lock on a different aReadmark[] slot.
**
** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
*/
static int walUpgradeReadlock(Wal *pWal){
int cnt;
int rc;
assert( pWal->writeLock && pWal->readLock==0 );
walUnlockShared(pWal, WAL_READ_LOCK(0));
pWal->readLock = -1;
cnt = 0;
do{
int notUsed;
rc = walTryBeginRead(pWal, ¬Used, 1, ++cnt);
}while( rc==WAL_RETRY );
assert( (rc&0xff)!=SQLITE_BUSY ); /* BUSY not possible when useWal==1 */
testcase( (rc&0xff)==SQLITE_IOERR );
testcase( rc==SQLITE_PROTOCOL );
testcase( rc==SQLITE_OK );
return rc;
}
int sqlite3WalUpgradeSnapshot(Wal *pWal){
int rc = SQLITE_OK;
assert( pWal->writeLock );
memcpy(&pWal->hdr, (void*)walIndexHdr(pWal), sizeof(WalIndexHdr));
/* If this client has its read-lock on slot aReadmark[0] and the entire
** wal has not been checkpointed, switch it to a different slot. Otherwise
** any reads performed between now and committing the transaction will
** read from the old snapshot - not the one just upgraded to. */
if( pWal->readLock==0 && pWal->hdr.mxFrame!=walCkptInfo(pWal)->nBackfill ){
rc = walUpgradeReadlock(pWal);
}
return rc;
}
/*
** End a write transaction. The commit has already been done. This
** routine merely releases the lock.
*/
int sqlite3WalEndWriteTransaction(Wal *pWal){
................................................................................
**
** SQLITE_OK is returned if no error is encountered (regardless of whether
** or not pWal->hdr.mxFrame is modified). An SQLite error code is returned
** if an error occurs.
*/
static int walRestartLog(Wal *pWal){
int rc = SQLITE_OK;
if( pWal->readLock==0 ){
volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
assert( pInfo->nBackfill==pWal->hdr.mxFrame );
if( pInfo->nBackfill>0 ){
u32 salt1;
sqlite3_randomness(4, &salt1);
................................................................................
** to handle if this transaction is rolled back. */
walRestartHdr(pWal, salt1);
walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
}else if( rc!=SQLITE_BUSY ){
return rc;
}
}
/* Regardless of whether or not the wal file was restarted, change the
** read-lock held by this client to a slot other than aReadmark[0].
** Clients with a lock on aReadmark[0] read from the database file
** only - never from the wal file. This means that if a writer holding
** a lock on aReadmark[0] were to commit a transaction but not close the
** read-transaction, subsequent read operations would read directly from
** the database file - ignoring the new pages just appended
** to the wal file. */
rc = walUpgradeReadlock(pWal);
}
return rc;
}
/*
** Information about the current state of the WAL file and where
** the next fsync should occur - passed from sqlite3WalFrames() into
|
Changes to src/wal.h.
123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 |
/* Return true if the argument is non-NULL and the WAL module is using
** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
** WAL module is using shared-memory, return false.
*/
int sqlite3WalHeapMemory(Wal *pWal);
int sqlite3WalLockForCommit(Wal *pWal, PgHdr *pPg, Bitvec *pRead);
void sqlite3WalUpgradeSnapshot(Wal *pWal);
#ifdef SQLITE_ENABLE_ZIPVFS
/* If the WAL file is not empty, return the number of bytes of content
** stored in each frame (i.e. the db page-size when the WAL was created).
*/
int sqlite3WalFramesize(Wal *pWal);
#endif
#endif /* ifndef SQLITE_OMIT_WAL */
#endif /* _WAL_H_ */
|
| |
123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 |
/* Return true if the argument is non-NULL and the WAL module is using
** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
** WAL module is using shared-memory, return false.
*/
int sqlite3WalHeapMemory(Wal *pWal);
int sqlite3WalLockForCommit(Wal *pWal, PgHdr *pPg, Bitvec *pRead);
int sqlite3WalUpgradeSnapshot(Wal *pWal);
#ifdef SQLITE_ENABLE_ZIPVFS
/* If the WAL file is not empty, return the number of bytes of content
** stored in each frame (i.e. the db page-size when the WAL was created).
*/
int sqlite3WalFramesize(Wal *pWal);
#endif
#endif /* ifndef SQLITE_OMIT_WAL */
#endif /* _WAL_H_ */
|
Changes to test/unlocked3.test.
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...
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|
. -----------------------
4 {1i}
5 {1d 2i}
. -----------------------
6 {1iii 2iii 3iii 4iii}
7 {1di 2id 3iii 4ddd}
8 {1iii 2iii 3iii 4iii}
} {
# 9 {1D 2II}
if {[string range $oplist 0 0]=="-"} {
reset_db
create_schema
continue
}
foreach db $DBLIST { sqlite3 $db test.db }
................................................................................
}
foreach db $DBLIST { $db eval "COMMIT" }
db eval {PRAGMA integrity_check}
} {ok}
foreach db $DBLIST {
if {$db=="db2"} breakpoint
$db close
}
}
finish_test
|
<
>
<
<
|
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...
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|
. -----------------------
4 {1i}
5 {1d 2i}
. -----------------------
6 {1iii 2iii 3iii 4iii}
7 {1di 2id 3iii 4ddd}
8 {1iii 2iii 3iii 4iii}
9 {1D 2II}
} {
if {[string range $oplist 0 0]=="-"} {
reset_db
create_schema
continue
}
foreach db $DBLIST { sqlite3 $db test.db }
................................................................................
}
foreach db $DBLIST { $db eval "COMMIT" }
db eval {PRAGMA integrity_check}
} {ok}
foreach db $DBLIST {
$db close
}
}
finish_test
|