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Overview
| Comment: | If a reader attempts to upgrade to a writer, but is not reading the most recent database snapshot, return SQLITE_BUSY. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | wal |
| Files: | files | file ages | folders |
| SHA1: |
837d82a92977cbfa0963411daf8160d2 |
| User & Date: | dan 2010-04-30 15:24:44.000 |
References
|
2010-04-30
| ||
| 16:24 | Reapply commits [837d82a929] and [c05e7dca17] that were accidentally overwritten. (check-in: 598de52700 user: dan tags: wal) | |
Context
|
2010-04-30
| ||
| 15:49 | When closing a WAL connection, attempt an exclusive lock on the database file. If the lock is obtained, checkpoint the database and delete the wal and wal-index files. (check-in: c05e7dca17 user: dan tags: wal) | |
| 15:24 | If a reader attempts to upgrade to a writer, but is not reading the most recent database snapshot, return SQLITE_BUSY. (check-in: 837d82a929 user: dan tags: wal) | |
| 14:39 | Separate the concepts of underlying storage size and mapped size in the VFS shared-memory implementation. (check-in: 4cbe49f13f user: drh tags: wal) | |
Changes
Changes to src/wal.c.
| ︙ | ︙ | |||
1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 |
** been overwritten by another writer, SQLITE_BUSY is returned.
*/
int sqlite3WalWriteLock(Wal *pWal, int op){
int rc;
if( op ){
assert( pWal->lockState == SQLITE_SHM_READ );
rc = walSetLock(pWal, SQLITE_SHM_WRITE);
}else if( pWal->lockState==SQLITE_SHM_WRITE ){
rc = walSetLock(pWal, SQLITE_SHM_READ);
}
return rc;
}
/*
| > > > > > > > > > > > > > > > > > > | 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 |
** been overwritten by another writer, SQLITE_BUSY is returned.
*/
int sqlite3WalWriteLock(Wal *pWal, int op){
int rc;
if( op ){
assert( pWal->lockState == SQLITE_SHM_READ );
rc = walSetLock(pWal, SQLITE_SHM_WRITE);
/* If this connection is not reading the most recent database snapshot,
** it is not possible to write to the database. In this case release
** the write locks and return SQLITE_BUSY.
*/
if( rc==SQLITE_OK ){
rc = walIndexMap(pWal, -1);
if( rc==SQLITE_OK
&& memcmp(&pWal->hdr, pWal->pWiData, sizeof(WalIndexHdr))
){
rc = SQLITE_BUSY;
}
walIndexUnmap(pWal);
if( rc!=SQLITE_OK ){
walSetLock(pWal, SQLITE_SHM_READ);
}
}
}else if( pWal->lockState==SQLITE_SHM_WRITE ){
rc = walSetLock(pWal, SQLITE_SHM_READ);
}
return rc;
}
/*
|
| ︙ | ︙ |