Re: getting to beta

On Thu, Apr 21, 2011 at 12:32 PM, Kevin Grittner
<Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
>> 1. All of the SSI patches have been dealt with.
>
> I'll add the non-serializable UPDATE performance issue.  Dan has
> been benchmarking to try to find a worst case; I don't want to speak
> for him too much, but as he was headed off to lecture a class he
> sent me results so far, and with beta so close I figure I should
> pass along a rough outline.  The worst case he has been able to
> construct so far was running 32 active processes on a 16 processor
> machine in an update-mostly mix against a database on tmpfs (so no
> disk writes) on a dataset which fits inside shared_memory.  This was
> able to generate enough contention on an exclusive LW lock to cause
> a 0.7% slowdown.
>
> Speaking for myself, I believe we'll be able to provide a very small
> patch to eliminate this.  Probably today or tomorrow.  While in a
> less extreme runtime environment it would probably be hard to pick
> out a performance impact in the normal noise, I expect the fix to be
> small and safe enough to be worth doing.
>
> I do feel that it would be good to apply the one-line fix Heikki
> posted, which is orthogonal and needed in any event.  That would
> give a little time for others to easily test it before beta.

Please add that patch to the open items list if it is not there already.

--
Robert Haas
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