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

OK, this is the way to fix for 8.0 and earlier.  It is up to you about
8.1.  I think we can handle the larger patch if we do another RC.

---------------------------------------------------------------------------

Tom Lane wrote:
> 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
> 

Content-Description: slru-race-2.patch

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