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Make sure PRAGMA data_version is updated even if the cache is empty when

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another connection changes the database.

FossilOrigin-Name: cf48eb608af9102a8def2a5b7f5f7b348548116f
This commit is contained in:
drh
2014-12-31 14:18:48 +00:00
parent e895b87389
commit 542d55865c
4 changed files with 20 additions and 20 deletions
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21
src/pager.c
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@@ -647,6 +647,7 @@ struct Pager {
u8 doNotSpill; /* Do not spill the cache when non-zero */
u8 subjInMemory; /* True to use in-memory sub-journals */
u8 bUseFetch; /* True to use xFetch() */
u8 hasBeenUsed; /* True if any content previously read from this pager*/
Pgno dbSize; /* Number of pages in the database */
Pgno dbOrigSize; /* dbSize before the current transaction */
Pgno dbFileSize; /* Number of pages in the database file */
@@ -3897,7 +3898,7 @@ static int pagerAcquireMapPage(
PgHdr **ppPage /* OUT: Acquired page object */
){
PgHdr *p; /* Memory mapped page to return */
if( pPager->pMmapFreelist ){
*ppPage = p = pPager->pMmapFreelist;
pPager->pMmapFreelist = p->pDirty;
@@ -5128,16 +5129,12 @@ int sqlite3PagerSharedLock(Pager *pPager){
);
}
if( !pPager->tempFile && (
pPager->pBackup
|| sqlite3PcachePagecount(pPager->pPCache)>0
|| USEFETCH(pPager)
)){
/* The shared-lock has just been acquired on the database file
** and there are already pages in the cache (from a previous
** read or write transaction). Check to see if the database
** has been modified. If the database has changed, flush the
** cache.
if( !pPager->tempFile && pPager->hasBeenUsed ){
/* The shared-lock has just been acquired then check to
** see if the database has been modified. If the database has changed,
** flush the cache. The pPager->hasBeenUsed flag prevents this from
** occurring on the very first access to a file, in order to save a
** single unnecessary sqlite3OsRead() call at the start-up.
**
** Database changes is detected by looking at 15 bytes beginning
** at offset 24 into the file. The first 4 of these 16 bytes are
@@ -5302,6 +5299,7 @@ int sqlite3PagerAcquire(
if( pgno==0 ){
return SQLITE_CORRUPT_BKPT;
}
pPager->hasBeenUsed = 1;
/* If the pager is in the error state, return an error immediately.
** Otherwise, request the page from the PCache layer. */
@@ -5451,6 +5449,7 @@ DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
assert( pgno!=0 );
assert( pPager->pPCache!=0 );
pPage = sqlite3PcacheFetch(pPager->pPCache, pgno, 0);
assert( pPage==0 || pPager->hasBeenUsed );
return sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pPage);
}