On Tue, 2005-02-15 at 15:21, Joel Fradkin wrote:
> Us? :) Can you provide some more details?
>
> Hardware configuration,
> Dell 6560 4 processor, 8 gig memory, I think I have Postgres on two raids
four processors, or two hyperthreaded cpus? My experience has been that
hyperthreading usually doesn't help, and often hurts performance. This
may have improved with later model 2.6 kernels.
> separate from the OS (pgsql is a raid 10 4 10kdrive array) and /wal is 2 15k
> drives). I am running postgres 8 and am using the conf in
> /var/lib/pgslq/data to point the data at /pgsql and a link to point the /wal
> I set up inside the /pgsql/data folder to /wal.
Which RAID Controller are you using? Does it have battery backed cache?
> I have cut out most of the query but even the first join makes it go to 27
> seconds. In MSSQL with the first two left outers it takes 3 seconds.
Are the columns you are joining on the same type? Are they integers
(the fastest) or numerics (slow) or text (also slow)?
Is there a reason you're joining on so many different fields for each
table? If there is a good model of FK relations, that isn't usually
necessary.
IT looks kinda like there's some redundancy in the join on clauses by
how may of them are from all over the place in there.