Robert Haas <robertmh...@gmail.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. -Kevin
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