Re: 8.3devel slower than 8.2 under read-only load

FWIW,

>
> Please do tests of at least 2 minutes duration. A 1.25 second test isn't
> enough. Please confirm you have VACUUM ANALYZED each db beforehand.
>
> Have you checked that the EXPLAIN ANALYZEs are essentially identical
> also? Is the data identical on both systems?
>

I've been running some fairly heavy read-only tests (5 minutes duration) against 8.3beta2 and 8.2.5 and 8.1.10 and are getting slightly faster numbers for 8.2.5 over 8.1 and 8.3beta2 looks consistently faster by a few percent. This is heavily oriented to postGIS queries so your mileage may vary. But so far I haven't seen any red flags or show stoppers from my (limited) perspective. There are some changes to the config files but I don't have details at hand.

Initial tests are always faster; we usually throw them out and run for real numbers starting with 3rd tests to make sure we don't jump at cache issues. For the most part we only care about performance with as much of the database in cache as we can so those initial tests aren;t of much use.

(Sorry for the poor posting -- challenged mail client)

HTH,

Greg Williamson
Senior DBA
GlobeXplorer LLC, a DigitalGlobe company

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