@ -8,7 +8,7 @@
* Portions Copyright ( c ) 1994 , Regents of the University of California
*
* IDENTIFICATION
* $ PostgreSQL : pgsql / src / backend / access / nbtree / nbtxlog . c , v 1.63 2010 / 03 / 19 10 : 41 : 22 sriggs Exp $
* $ PostgreSQL : pgsql / src / backend / access / nbtree / nbtxlog . c , v 1.64 2010 / 03 / 28 09 : 27 : 01 sriggs Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
@ -553,6 +553,139 @@ btree_xlog_vacuum(XLogRecPtr lsn, XLogRecord *record)
UnlockReleaseBuffer ( buffer ) ;
}
/*
* Get the latestRemovedXid from the heap pages pointed at by the index
* tuples being deleted . This puts the work for calculating latestRemovedXid
* into the recovery path rather than the primary path .
*
* It ' s possible that this generates a fair amount of I / O , since an index
* block may have hundreds of tuples being deleted . Repeat accesses to the
* same heap blocks are common , though are not yet optimised .
*
* XXX optimise later with something like XLogPrefetchBuffer ( )
*/
static TransactionId
btree_xlog_delete_get_latestRemovedXid ( XLogRecord * record )
{
OffsetNumber * unused ;
Buffer ibuffer , hbuffer ;
Page ipage , hpage ;
ItemId iitemid , hitemid ;
IndexTuple itup ;
HeapTupleHeader htuphdr ;
BlockNumber hblkno ;
OffsetNumber hoffnum ;
TransactionId latestRemovedXid = InvalidTransactionId ;
TransactionId htupxid = InvalidTransactionId ;
int i ;
int num_unused , num_redirect , num_dead ;
xl_btree_delete * xlrec = ( xl_btree_delete * ) XLogRecGetData ( record ) ;
/*
* Get index page
*/
ibuffer = XLogReadBuffer ( xlrec - > node , xlrec - > block , false ) ;
if ( ! BufferIsValid ( ibuffer ) )
return InvalidTransactionId ;
ipage = ( Page ) BufferGetPage ( ibuffer ) ;
/*
* Loop through the deleted index items to obtain the TransactionId
* from the heap items they point to .
*/
unused = ( OffsetNumber * ) ( ( char * ) xlrec + SizeOfBtreeDelete ) ;
for ( i = 0 ; i < xlrec - > nitems ; i + + )
{
/*
* Identify the index tuple about to be deleted
*/
iitemid = PageGetItemId ( ipage , unused [ i ] ) ;
itup = ( IndexTuple ) PageGetItem ( ipage , iitemid ) ;
/*
* Locate the heap page that the index tuple points at
*/
hblkno = ItemPointerGetBlockNumber ( & ( itup - > t_tid ) ) ;
hbuffer = XLogReadBuffer ( xlrec - > hnode , hblkno , false ) ;
if ( ! BufferIsValid ( hbuffer ) )
{
UnlockReleaseBuffer ( ibuffer ) ;
return InvalidTransactionId ;
}
hpage = ( Page ) BufferGetPage ( hbuffer ) ;
/*
* Look up the heap tuple header that the index tuple points at
* by using the heap node supplied with the xlrec . We can ' t use
* heap_fetch , since it uses ReadBuffer rather than XLogReadBuffer .
* Note that we are not looking at tuple data here , just headers .
*/
hoffnum = ItemPointerGetOffsetNumber ( & ( itup - > t_tid ) ) ;
hitemid = PageGetItemId ( hpage , hoffnum ) ;
/*
* Follow any redirections until we find something useful .
*/
while ( ItemIdIsRedirected ( hitemid ) )
{
num_redirect + + ;
hoffnum = ItemIdGetRedirect ( hitemid ) ;
hitemid = PageGetItemId ( hpage , hoffnum ) ;
CHECK_FOR_INTERRUPTS ( ) ;
}
/*
* If the heap item has storage , then read the header . Some LP_DEAD
* items may not be accessible , so we ignore them .
*/
if ( ItemIdHasStorage ( hitemid ) )
{
htuphdr = ( HeapTupleHeader ) PageGetItem ( hpage , hitemid ) ;
/*
* Get the heap tuple ' s xmin / xmax and ratchet up the latestRemovedXid .
* No need to consider xvac values here .
*/
htupxid = HeapTupleHeaderGetXmin ( htuphdr ) ;
if ( TransactionIdFollows ( htupxid , latestRemovedXid ) )
latestRemovedXid = htupxid ;
htupxid = HeapTupleHeaderGetXmax ( htuphdr ) ;
if ( TransactionIdFollows ( htupxid , latestRemovedXid ) )
latestRemovedXid = htupxid ;
}
else if ( ItemIdIsDead ( hitemid ) )
{
/*
* Conjecture : if hitemid is dead then it had xids before the xids
* marked on LP_NORMAL items . So we just ignore this item and move
* onto the next , for the purposes of calculating latestRemovedxids .
*/
num_dead + + ;
}
else
{
Assert ( ! ItemIdIsUsed ( hitemid ) ) ;
num_unused + + ;
}
UnlockReleaseBuffer ( hbuffer ) ;
}
UnlockReleaseBuffer ( ibuffer ) ;
Assert ( num_unused = = 0 ) ;
/*
* Note that if all heap tuples were LP_DEAD then we will be
* returning InvalidTransactionId here . This seems very unlikely
* in practice .
*/
return latestRemovedXid ;
}
static void
btree_xlog_delete ( XLogRecPtr lsn , XLogRecord * record )
{
@ -584,12 +717,10 @@ btree_xlog_delete(XLogRecPtr lsn, XLogRecord *record)
if ( record - > xl_len > SizeOfBtreeDelete )
{
OffsetNumber * unused ;
OffsetNumber * unend ;
unused = ( OffsetNumber * ) ( ( char * ) xlrec + SizeOfBtreeDelete ) ;
unend = ( OffsetNumber * ) ( ( char * ) xlrec + record - > xl_len ) ;
PageIndexMultiDelete ( page , unused , unend - unused ) ;
PageIndexMultiDelete ( page , unused , xlrec - > nitems ) ;
}
/*
@ -830,6 +961,7 @@ btree_redo(XLogRecPtr lsn, XLogRecord *record)
* from individual btree vacuum records on that index .
*/
{
TransactionId latestRemovedXid = btree_xlog_delete_get_latestRemovedXid ( record ) ;
xl_btree_delete * xlrec = ( xl_btree_delete * ) XLogRecGetData ( record ) ;
/*
@ -839,7 +971,7 @@ btree_redo(XLogRecPtr lsn, XLogRecord *record)
* here is worth some thought and possibly some effort to
* improve .
*/
ResolveRecoveryConflictWithSnapshot ( xlrec - > latestRemovedXid , xlrec - > node ) ;
ResolveRecoveryConflictWithSnapshot ( latestRemovedXid , xlrec - > node ) ;
}
break ;
@ -1012,10 +1144,10 @@ btree_desc(StringInfo buf, uint8 xl_info, char *rec)
{
xl_btree_delete * xlrec = ( xl_btree_delete * ) rec ;
appendStringInfo ( buf , " delete: rel %u/%u/%u; blk %u, latestRemovedXid %u " ,
xlrec - > node . spcNode , xlrec - > node . dbNode ,
xlrec - > node . relNode , xlrec - > block ,
xlrec - > latestRemovedXid ) ;
appendStringInfo ( buf , " delete: index %u/%u/%u; iblk %u, heap %u/%u/%u; " ,
xlrec - > node . spcNode , xlrec - > node . dbNode , xlrec - > node . relNode ,
xlrec - > block ,
xlrec - > hnode . spcNode , xlrec - > hnode . dbNode , xlrec - > hnode . relNode ) ;
break ;
}
case XLOG_BTREE_DELETE_PAGE :
Simon Riggs
16 years ago