database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-08-07 02:42:48 +03:00
Code Activity

When attempting to restart a wal file, make any required calls to sqlite3_randomness() before waiting on or checking for wal file readers. This restores the behaviour exhibited by the trunk.

Browse Source 
FossilOrigin-Name: 6ee08769f0ffbb3d620c66b89180ece7782dc820
This commit is contained in:
dan
2014-12-02 19:35:09 +00:00
parent f26a1549ac
commit 0fe8c1b967
3 changed files with 17 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
src/wal.c
View File

@@ -1635,15 +1635,19 @@ static int walPagesize(Wal *pWal){
** This function updates the shared-memory structures so that the next
** client to write to the database (which may be this one) does so by
** writing frames into the start of the log file.
**
** The value of parameter salt1 is used as the aSalt[1] value in the
** new wal-index header. It should be passed a pseudo-random value (i.e.
** one obtained from sqlite3_randomness()).
*/
static void walRestartHdr(Wal *pWal){
static void walRestartHdr(Wal *pWal, u32 salt1){
volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
int i; /* Loop counter */
u32 *aSalt = pWal->hdr.aSalt; /* Big-endian salt values */
pWal->nCkpt++;
pWal->hdr.mxFrame = 0;
sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
sqlite3_randomness(4, &aSalt[1]);
memcpy(&pWal->hdr.aSalt[1], &salt1, 4);
walIndexWriteHdr(pWal);
pInfo->nBackfill = 0;
pInfo->aReadMark[1] = 0;
@@ -1813,6 +1817,8 @@ static int walCheckpoint(
if( pInfo->nBackfill<pWal->hdr.mxFrame ){
rc = SQLITE_BUSY;
}else if( eMode>=SQLITE_CHECKPOINT_RESTART ){
u32 salt1;
sqlite3_randomness(4, &salt1);
assert( mxSafeFrame==pWal->hdr.mxFrame );
rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(1), WAL_NREADER-1);
if( rc==SQLITE_OK ){
@@ -1828,7 +1834,7 @@ static int walCheckpoint(
** the wal-index header do not match the contents of the
** file-system. To avoid this, update the wal-index header to
** indicate that the log file contains zero valid frames. */
walRestartHdr(pWal);
walRestartHdr(pWal, salt1);
rc = sqlite3OsTruncate(pWal->pWalFd, 0);
}
walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
@@ -2649,7 +2655,7 @@ static int walRestartLog(Wal *pWal){
** at this point. But updating the actual wal-index header is also
** safe and means there is no special case for sqlite3WalUndo()
** to handle if this transaction is rolled back. */
walRestartHdr(pWal);
walRestartHdr(pWal, salt1);
walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
}else if( rc!=SQLITE_BUSY ){
return rc;