Re: [PERFORM] Slow select performance despite seemingly reasonable query plan

2009-05-07 Thread David Brain
Hi, Some answers in-line: > > Has there been a performance *change*, or are you just concerned about a > query which doesn't seem to use "enough" disc bandwidth? Performance has degraded noticeably over the past few days. > Certainly random access like this index scan can be extremely slow. 2-4

Re: [PERFORM] Slow select performance despite seemingly reasonable query plan

2009-05-07 Thread David Brain
Hi, Interesting, for one index on one partition: idx_scan: 329 idx_tup_fetch: 8905730 So maybe a reindex would help? David. On Thu, May 7, 2009 at 10:26 AM, Scott Mead wrote: > On Thu, May 7, 2009 at 10:14 AM, David Brain wrote: >> >> Hi, >> >> Some context, we

[PERFORM] Slow select performance despite seemingly reasonable query plan

2009-05-07 Thread David Brain
Hi, Some context, we have a _lot_ of data, > 1TB, mostly in 1 'table' - the 'datatable' in the example below although in order to improve performance this table is partitioned (by date range) into a number of partition tables. Each partition contains up to 20GB of data (tens of millons of rows),

[PERFORM] 1 or 2 servers for large DB scenario.

2008-01-25 Thread David Brain
Hi, I'd appreciate some assistance in working through what would be the optimal configuration for the following situation. We currently have one large DB (~1.2TB on disk), that essentially consists of 1 table with somewhere in the order of 500 million rows , this database has daily insert

Re: [PERFORM] Potential memory usage issue [resolved]

2007-03-22 Thread David Brain
he -B 1024 allowed the settings to revert to the file specified values. So now I'm back to using ~50k buffers again and things are running a little more swiftly, and according to pg_buffercache I'm using 49151 of them (-: Thanks again to those who helped me track this down. Dav

Re: [PERFORM] Potential memory usage issue

2007-03-22 Thread David Brain
you'd use as a diagnostic on this - I just installed the module - but I'm not entirely clear as to what the output is actually showing me and/or what would be considered good or bad. Thanks, David. -- David Brain - bandwidth.com [EMAIL PROTECTED] ---(end of

Re: [PERFORM] Potential memory usage issue

2007-03-22 Thread David Brain
Hi, Thanks for the response. Bill Moran wrote: In response to David Brain <[EMAIL PROTECTED]>: I recently migrated one of our large (multi-hundred GB) dbs from an Intel 32bit platform (Dell 1650 - running 8.1.3) to a 64bit platform (Dell 1950 - running 8.1.5). However I am not seei

[PERFORM] Potential memory usage issue

2007-03-22 Thread David Brain
from here? Thanks, David. -- David Brain - bandwidth.com [EMAIL PROTECTED] ---(end of broadcast)--- TIP 6: explain analyze is your friend