If you have 3 1.5GB tables then you might as well go for 4GB while you're at it. Make sure you've got a bigmem kernel either running or available, and boost effective_cache_size by whatever amount you increase the RAM by. We run a Quad Xeon/4GB server on Redhat 7.3 and it's solid as a rock.
There is no way I know of to get indexes preferentially cached over data though. Matt > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Nick > Fankhauser > Sent: 17 December 2003 19:57 > To: [EMAIL PROTECTED] Org > Subject: [PERFORM] Adding RAM: seeking advice & warnings of hidden > "gotchas" > > > Hi- > > After having done my best to squeeze better performance out of our > application by tuning within our existing resources, I'm falling back on > adding memory as a short-term solution while we get creative for > a long-term > fix. I'm curious about what experiences others have had with the > process of > adding big chunks of RAM. In particular, if I'm trying to encourage the OS > to cache more of my index information in RAM, what sort of configuration > should I do at both the PostgreSQL and OS level? > > In a slightly off-topic vein, I'd also like to hear about it if > anyone knows > about any gotchas at the OS level that might become a problem. > > The server is a dual processor Athlon 1.2GHz box with hardware > SCSI RAID. It > currently has 1 GB RAM, and we're planning to add one GB more for > a total of > 2GB. The OS is Debian Linux Kernel 2.4.x, and we're on PostgreSQL v7.3.2 > > My current memory related settings are: > > SHMMAX and SHMALL set to 128MB (OS setting) > shared buffers 8192 (64MB) > sort_mem 16384 (16MB) > effective_cache_size 65536 (512MB) > > > We support up to 70 active users, sharing a connection pool of 16 > connections. Most of the queries center around 3 tables that are about 1.5 > GB each. > > > Thanks. > -Nick > > --------------------------------------------------------------------- > Nick Fankhauser > > [EMAIL PROTECTED] Phone 1.765.965.7363 Fax 1.765.962.9788 > doxpop - Court records at your fingertips - http://www.doxpop.com/ > > > > ---------------------------(end of broadcast)--------------------------- > TIP 7: don't forget to increase your free space map settings > ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
