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Within a backup operation, ensure that a read-transaction is opened on the source database before its page size is read. This ensures the page-size used to write to the backup database is the same as its actual page-size, which is important for ZipVFS databases.

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FossilOrigin-Name: 7908fc604991d81140c182b97981fd724ad126ae
This commit is contained in:
dan
2016-09-02 17:18:20 +00:00
parent e5a0cfa161
commit 033564cca9
3 changed files with 23 additions and 16 deletions
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25
src/backup.c
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@@ -196,7 +196,6 @@ sqlite3_backup *sqlite3_backup_init(
p->isAttached = 0;
if( 0==p->pSrc || 0==p->pDest
|| setDestPgsz(p)==SQLITE_NOMEM
|| checkReadTransaction(pDestDb, p->pDest)!=SQLITE_OK
){
/* One (or both) of the named databases did not exist or an OOM
@@ -384,14 +383,6 @@ int sqlite3_backup_step(sqlite3_backup *p, int nPage){
rc = SQLITE_OK;
}
/* Lock the destination database, if it is not locked already. */
if( SQLITE_OK==rc && p->bDestLocked==0
&& SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2))
){
p->bDestLocked = 1;
sqlite3BtreeGetMeta(p->pDest, BTREE_SCHEMA_VERSION, &p->iDestSchema);
}
/* If there is no open read-transaction on the source database, open
** one now. If a transaction is opened here, then it will be closed
** before this function exits.
@@ -401,6 +392,22 @@ int sqlite3_backup_step(sqlite3_backup *p, int nPage){
bCloseTrans = 1;
}
/* If the destination database has not yet been locked (i.e. if this
** is the first call to backup_step() for the current backup operation),
** try to set its page size to the same as the source database. This
** is especially important on ZipVFS systems, as in that case it is
** not possible to create a database file that uses one page size by
** writing to it with another. */
if( p->bDestLocked==0 ) setDestPgsz(p);
/* Lock the destination database, if it is not locked already. */
if( SQLITE_OK==rc && p->bDestLocked==0
&& SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2))
){
p->bDestLocked = 1;
sqlite3BtreeGetMeta(p->pDest, BTREE_SCHEMA_VERSION, &p->iDestSchema);
}
/* Do not allow backup if the destination database is in WAL mode
** and the page sizes are different between source and destination */
pgszSrc = sqlite3BtreeGetPageSize(p->pSrc);