NotificationsYou must be signed in to change notification settings
Fork6
Star31

Commit44445b2

committed

Set the process latch when processing recovery conflict interrupts.

Because RecoveryConflictInterrupt() didn't set the process latchanything using the latter to wait for events didn't get notified aboutrecovery conflicts. Most latch users are never the target of recoveryconflicts, which explains the lack of reports about this untilnow.Since 9.3 two possible affected users exist though: The sql callablepg_sleep() now uses latches to wait and background workers areexpected to use latches in their main loop. Both would currently waituntil the end of WaitLatch's timeout.Fix by adding a SetLatch() to RecoveryConflictInterrupt(). It'd alsobe possible to fix the issue by having each latch user setset_latch_on_sigusr1. That seems failure prone and though, as most ofthese callsites won't often receive recovery conflicts and thus willlikely only be tested against normal query cancels et al. It'd also beunnecessarily verbose.Backpatch to 9.1 where latches were introduced. Arguably 9.3 would besufficient, because that's where pg_sleep() was converted to waitingon the latch and background workers got introduced; but there could beuser level code making use of the latch pre 9.3.

1 parent5eebb8d commit44445b2Copy full SHA for 44445b2

File tree

1 file changed

+10

-0

lines changed

src/backend/tcop
- postgres.c

1 file changed

+10

-0

lines changed

`‎src/backend/tcop/postgres.c`

Lines changed: 10 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -2806,6 +2806,16 @@ RecoveryConflictInterrupt(ProcSignalReason reason)`
`2806`	`2806`	`}`
`2807`	`2807`	`}`
`2808`	`2808`
	`2809`	`+/*`
	`2810`	`+ * Set the process latch. This function essentially emulates signal`
	`2811`	`+ * handlers like die() and StatementCancelHandler() and it seems prudent`
	`2812`	`+ * to behave similarly as they do. Alternatively all plain backend code`
	`2813`	`+ * waiting on that latch, expecting to get interrupted by query cancels et`
	`2814`	`+ * al., would also need to set set_latch_on_sigusr1.`
	`2815`	`+ */`
	`2816`	`+if (MyProc)`
	`2817`	`+SetLatch(&MyProc->procLatch);`
	`2818`	`+`
`2809`	`2819`	`errno=save_errno;`
`2810`	`2820`	`}`
`2811`	`2821`

0 commit comments

Comments

(0)

Movatterモバイル変換

Navigation Menu

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

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Commit44445b2

File tree

1 file changed

1 file changed

`‎src/backend/tcop/postgres.c`

0 commit comments