Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commited962fd

Browse files
committed
Ensure that seqscans check for interrupts at least once per page.
If a seqscan encounters many consecutive pages containing only dead tuples,it can remain in the loop in heapgettup for a long time, and there was noCHECK_FOR_INTERRUPTS anywhere in that loop. This meant there werereal-world situations where a query would be effectively uncancelable forlong stretches. Add a check placed to occur once per page, which should beenough to provide reasonable response time without adding any measurableoverhead.Report and patch by Merlin Moncure (though I tweaked it a bit).Back-patch to all supported branches.
1 parent92a953f commited962fd

File tree

1 file changed

+7
-0
lines changed

1 file changed

+7
-0
lines changed

‎src/backend/access/heap/heapam.c

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -222,6 +222,13 @@ heapgetpage(HeapScanDesc scan, BlockNumber page)
222222
scan->rs_cbuf=InvalidBuffer;
223223
}
224224

225+
/*
226+
* Be sure to check for interrupts at least once per page. Checks at
227+
* higher code levels won't be able to stop a seqscan that encounters
228+
* many pages' worth of consecutive dead tuples.
229+
*/
230+
CHECK_FOR_INTERRUPTS();
231+
225232
/* read page using selected strategy */
226233
scan->rs_cbuf=ReadBufferExtended(scan->rs_rd,MAIN_FORKNUM,page,
227234
RBM_NORMAL,scan->rs_strategy);

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp