SQLite: Check-in [04dcba6b]

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Overview

Comment:	If walLockExclusive() fails for reasons other than SQLITE_BUSY inside of walRestartLog() then propagate that error back up to the application.
Downloads:	Tarball \| ZIP archive \| SQL archive
Timelines:	family \| ancestors \| descendants \| both \| trunk
Files:	files \| file ages \| folders
SHA1:	04dcba6b3379d2168609950ed919c8f743705333
User & Date:	drh 2010-10-05 15:41:06

Context

2010-10-05
17:02		Have the pager change to at least WRITER_CACHEMOD state before marking any pages as dirty (instead of immediately after). Otherwise, if an error occurs, the pager may be left in WRITER_LOCKED state with dirty pages in the cache. check-in: 471a4efb user: dan tags: trunk
15:41		If walLockExclusive() fails for reasons other than SQLITE_BUSY inside of walRestartLog() then propagate that error back up to the application. check-in: 04dcba6b user: drh tags: trunk
12:05		Avoid all memory allocation (and hence the possiblitity of OOM failure) in sqlite3_value_double() and sqlite3_column_double(). check-in: 4afdf970 user: drh tags: trunk

Changes

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Changes to src/wal.c.

** to the current log file, it is possible to overwrite the start of the
** existing log file with the new frames (i.e. "reset" the log). If so,
** it sets pWal->hdr.mxFrame to 0. Otherwise, pWal->hdr.mxFrame is left
** unchanged.
**
** 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 some error 
*/
static int walRestartLog(Wal *pWal){
  int rc = SQLITE_OK;
  int cnt;

  if( pWal->readLock==0 ){
    volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
................................................................................
        sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
        sqlite3_randomness(4, &aSalt[1]);
        walIndexWriteHdr(pWal);
        pInfo->nBackfill = 0;
        for(i=1; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
        assert( pInfo->aReadMark[0]==0 );
        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);


      }
    }
    walUnlockShared(pWal, WAL_READ_LOCK(0));
    pWal->readLock = -1;
    cnt = 0;
    do{
      int notUsed;

** to the current log file, it is possible to overwrite the start of the
** existing log file with the new frames (i.e. "reset" the log). If so,
** it sets pWal->hdr.mxFrame to 0. Otherwise, pWal->hdr.mxFrame is left
** unchanged.
**
** 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);
................................................................................
        sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
        sqlite3_randomness(4, &aSalt[1]);
        walIndexWriteHdr(pWal);
        pInfo->nBackfill = 0;
        for(i=1; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
        assert( pInfo->aReadMark[0]==0 );
        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;