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Avoid unnecessary page cache allocations when move a page while autovacuuming

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an in-memory database, since the allocation might fail making it impossible to
rollback the transaction.

FossilOrigin-Name: 9a429349ccc2fa9acd28365a86578f602e87dafb
This commit is contained in:
drh
2009-11-20 13:18:14 +00:00
parent d1414c58e5
commit 98829a65cd
4 changed files with 32 additions and 29 deletions
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23
src/pager.c
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@@ -5154,7 +5154,14 @@ int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
assert( !pPgOld || pPgOld->nRef==1 );
if( pPgOld ){
pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
sqlite3PcacheDrop(pPgOld);
if( MEMDB ){
/* Do not discard pages from an in-memory database since we might
** need to rollback later. Just move the page out of the way. */
assert( pPager->dbSizeValid );
sqlite3PcacheMove(pPgOld, pPager->dbSize+1);
}else{
sqlite3PcacheDrop(pPgOld);
}
}
origPgno = pPg->pgno;
@@ -5199,18 +5206,12 @@ int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
/*
** For an in-memory database, make sure the original page continues
** to exist, in case the transaction needs to roll back. We allocate
** the page now, instead of at rollback, because we can better deal
** with an out-of-memory error now. Ticket #3761.
** to exist, in case the transaction needs to roll back. Use pPgOld
** as the original page since it has already been allocated.
*/
if( MEMDB ){
DbPage *pNew;
rc = sqlite3PagerAcquire(pPager, origPgno, &pNew, 1);
if( rc!=SQLITE_OK ){
sqlite3PcacheMove(pPg, origPgno);
return rc;
}
sqlite3PagerUnref(pNew);
sqlite3PcacheMove(pPgOld, origPgno);
sqlite3PagerUnref(pPgOld);
}
return SQLITE_OK;