Horton

Re: slru.c race condition (was Re: [HACKERS] TRAP: FailedAssertion("!((itemid)->lp_flags & 0x01)", )

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: pgsql-patches@postgresql.org, Jim Nasby <jnasby@pervasive.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: 2005-10-31T18:13:52Z
Lists: pgsql-hackers 
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Well, then what real options do we have?  It seems the patch is just
> required for all branches.

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.  In situations where there's not a lot of SLRU I/O traffic it's
presumably negligible, but in a case like Jim's where there's evidently
a *whole* lot of traffic, it might be a killer.

			regards, tom lane