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Insert CHECK_FOR_INTERRUPTS() calls into btree and hash index scans at the

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points where we step right or left to the next page.  This should ensure
reasonable response time to a query cancel request during an unsuccessful
index scan, as seen in recent gripe from Marc Cousin.  It's a bit trickier
than it might seem at first glance, because CHECK_FOR_INTERRUPTS() is a no-op
if executed while holding a buffer lock.  So we have to do it just at the
point where we've dropped one page lock and not yet acquired the next.

Remove CHECK_FOR_INTERRUPTS calls at the top level of btgetbitmap and
hashgetbitmap, since they're pointless given the added checks.

I think that GIST is okay already --- at least, there's a CHECK_FOR_INTERRUPTS
at a plausible-looking place in gistnext().  I don't claim to know GIN well
enough to try to poke it for this, if indeed it has a problem at all.

This is a pre-existing issue, but in view of the lack of prior complaints
I'm not going to risk back-patching.
This commit is contained in:
Tom Lane 2009-05-05 19:36:32 +00:00
parent 2aa5ca952f
commit 8f348112f3
4 changed files with 21 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
src/backend/access/hash/hash.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hash.c,v 1.109 2009/03/24 20:17:11 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hash.c,v 1.110 2009/05/05 19:36:32 tgl Exp $
*
* NOTES
* This file contains only the public interface routines.
@ -22,7 +22,6 @@
#include "access/relscan.h"
#include "catalog/index.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "optimizer/cost.h"
#include "optimizer/plancat.h"
#include "storage/bufmgr.h"
@ -297,8 +296,6 @@ hashgetbitmap(PG_FUNCTION_ARGS)
{
bool add_tuple;
CHECK_FOR_INTERRUPTS();
/*
* Skip killed tuples if asked to.
*/

7
src/backend/access/hash/hashsearch.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashsearch.c,v 1.55 2009/01/01 17:23:35 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashsearch.c,v 1.56 2009/05/05 19:36:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -16,6 +16,7 @@
#include "access/hash.h"
#include "access/relscan.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "storage/bufmgr.h"
#include "utils/rel.h"
@ -74,6 +75,8 @@ _hash_readnext(Relation rel,
blkno = (*opaquep)->hasho_nextblkno;
_hash_relbuf(rel, *bufp);
*bufp = InvalidBuffer;
/* check for interrupts while we're not holding any buffer lock */
CHECK_FOR_INTERRUPTS();
if (BlockNumberIsValid(blkno))
{
*bufp = _hash_getbuf(rel, blkno, HASH_READ, LH_OVERFLOW_PAGE);
@ -94,6 +97,8 @@ _hash_readprev(Relation rel,
blkno = (*opaquep)->hasho_prevblkno;
_hash_relbuf(rel, *bufp);
*bufp = InvalidBuffer;
/* check for interrupts while we're not holding any buffer lock */
CHECK_FOR_INTERRUPTS();
if (BlockNumberIsValid(blkno))
{
*bufp = _hash_getbuf(rel, blkno, HASH_READ,

5
src/backend/access/nbtree/nbtree.c
View File

@ -12,7 +12,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.168 2009/03/24 20:17:12 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.169 2009/05/05 19:36:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -24,7 +24,6 @@
#include "catalog/index.h"
#include "catalog/storage.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
#include "storage/freespace.h"
#include "storage/indexfsm.h"
@ -315,8 +314,6 @@ btgetbitmap(PG_FUNCTION_ARGS)
*/
if (++so->currPos.itemIndex > so->currPos.lastItem)
{
CHECK_FOR_INTERRUPTS();
/* let _bt_next do the heavy lifting */
if (!_bt_next(scan, ForwardScanDirection))
break;

22
src/backend/access/nbtree/nbtsearch.c
View File

@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.119 2009/01/01 17:23:35 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.120 2009/05/05 19:36:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -18,6 +18,7 @@
#include "access/genam.h"
#include "access/nbtree.h"
#include "access/relscan.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "storage/bufmgr.h"
#include "utils/lsyscache.h"
@ -1126,16 +1127,16 @@ _bt_steppage(IndexScanDesc scan, ScanDirection dir)
for (;;)
{
/* if we're at end of scan, release the buffer and return */
/* release the previous buffer */
_bt_relbuf(rel, so->currPos.buf);
so->currPos.buf = InvalidBuffer;
/* if we're at end of scan, give up */
if (blkno == P_NONE || !so->currPos.moreRight)
{
_bt_relbuf(rel, so->currPos.buf);
so->currPos.buf = InvalidBuffer;
return false;
}
/* check for interrupts while we're not holding any buffer lock */
CHECK_FOR_INTERRUPTS();
/* step right one page */
so->currPos.buf = _bt_relandgetbuf(rel, so->currPos.buf,
blkno, BT_READ);
so->currPos.buf = _bt_getbuf(rel, blkno, BT_READ);
/* check for deleted page */
page = BufferGetPage(so->currPos.buf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
@ -1239,7 +1240,10 @@ _bt_walk_left(Relation rel, Buffer buf)
obknum = BufferGetBlockNumber(buf);
/* step left */
blkno = lblkno = opaque->btpo_prev;
buf = _bt_relandgetbuf(rel, buf, blkno, BT_READ);
_bt_relbuf(rel, buf);
/* check for interrupts while we're not holding any buffer lock */
CHECK_FOR_INTERRUPTS();
buf = _bt_getbuf(rel, blkno, BT_READ);
page = BufferGetPage(buf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);