| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
| Cc: | pgsql-patches(at)postgresql(dot)org, Jim Nasby <jnasby(at)pervasive(dot)com>, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
| Subject: | Re: slru.c race condition (was Re: [HACKERS] TRAP: FailedAssertion("!((itemid)->lp_flags & 0x01)", ) |
| Date: | 2005-10-31 18:46:35 |
| Message-ID: | 17961.1130784395@sss.pgh.pa.us |
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| Thread: | |
| Lists: | pgsql-hackers pgsql-patches |
I wrote:
> I think it would be possible to fix it in a less invasive way by taking
> and releasing the ControlLock an extra time in SimpleLruReadPage and
> SimpleLruWritePage. What's indeterminate about that is the performance
> cost.
Attached is an alternative patch that does it this way. I realized that
we could use LWLockConditionalAcquire to usually avoid any extra lock
traffic, so the performance cost may be negligible except under the very
heaviest of loads. I still like the bigger patch for 8.2 and forward,
because it's a lot cleaner, but this seems like a credible alternative
for 8.1 and back branches.
Comments?
regards, tom lane
| Attachment | Content-Type | Size |
|---|---|---|
| slru-race-2.patch | application/octet-stream | 8.2 KB |
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