Re: [PERFORM] Is disableing nested_loops a bad idea ?

2010-09-25 Thread Robert Haas
On Thu, Sep 16, 2010 at 10:13 AM, Franck Routier wrote: > Thanks Kevin and Samuel for your input. > > The point is we already made a lot of tweaking to try to tune postgresql > to behave correctly. I work with Damien, and here is a post he did in > july to explain the kind of problems we have > ht

Re: [PERFORM] turn off caching for performance test

2010-09-25 Thread Robert Haas
On Fri, Aug 27, 2010 at 1:57 PM, Scott Marlowe wrote: > On Thu, Aug 26, 2010 at 4:32 AM, Willy-Bas Loos wrote: >> Hi, >> >> I have a colleague that is convinced that the website is faster if >> enable_seqscan is turned OFF. >> I'm convinced of the opposite (better to leave it ON), but i would lik

Re: [PERFORM] Memory usage - indexes

2010-09-25 Thread Tobias Brox
On 25 September 2010 00:00, Greg Smith wrote: > Overindexed tables containing more columns than are actually selective is a > very popular source of PostgreSQL slowdowns.  It's easy to say "oh, I look > this data up using columns a,b,c, so lets put an index on a,b,c".  But if an > index on a alone