robcron <rocron@xxxxxxxx> writes: > Our IT group took over an app that we have running using postgres and it has > been on version 8.2.11 since we acquired it. It is time to get current, so > I have created instances of our production database that mirror exact > hardware for our existing implementation on version 8.2.11 (running Fedora > Core 8 - wow I know) and also version 9.1.6 on Fedora 17. I am able to > mimic the production 8.2 environment exactly without any of the load of > production and the same for the new 9.1 environment so there is no > perverting of numbers based on load that I can't control > Machines are Cloud based images running 4 (dual Core) Processors, with 15GB > of memory... AMAZON m1.Xlarge boxes - 64 bit OS. Hm ... Amazon cloud is not exactly known for providing rock-stable performance environment, but anyway the first thing I would have guessed at, seeing that the plans are basically the same, was a non-C locale setting. Another thing to check is whether the new machine has higher timing overhead --- is the speed difference the same when you just run the query, rather than EXPLAIN ANALYZE'ing it? (If not, contrib/pg_test_timing from 9.2 or later might yield useful data.) regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
