On Mon, 15 Sep 2003, scott.marlowe wrote: > On Mon, 15 Sep 2003, Joseph Bove wrote: > > > Stephan, > > > > I've run explain analyze a number of times and have gotten results between > > 5.5 and 7.5 seconds > > > > Attached is a typical output > > > > QUERY PLAN > > ------------------------------------- > > Aggregate (cost=9993.92..9993.92 rows=1 width=0) > > (actual time=7575.59..7575.59 rows=1 loops=1) > > -> Seq Scan on vetapview (cost=0.00..9771.34 rows=89034 width=0) > > (actual time=0.06..7472.20 > > rows=88910 loops=1) > > Total runtime: 7575.67 msec > > (3 rows) > > > > The only things changing are the actual time. The costs are constant. > > > > The relpages from pg_class for vetapview (the table in question) is 8881. > > > > At the end of this message is the exhaustive contents of postgresql.conf. > > The only settings I have attempted tuning are as follows: > > > > tcpip_socket = true > > max_connections = 100 > > shared_buffers = 5000 > > sort_mem = 8192 > > fsync = false > > A couple of things. > > 1: Is there an index on the parts of the query used for the where clause? > 2: What is your effect_cache_size set to? It needs to be set right for > your postgresql server to be able to take advantage of the kernel's cache > (i.e. use an index scan when the kernel is likely to have that data in > memory.)
Sorry, that should be effective_cache_size, not effect_cache_size. It's set in 8k blocks and is usually about how much buffer / cache you have left over after the machines "settles" after being up and running for a while. Fer instance, on my server, I show 784992K cache, and 42976K buff under top, so, that's 827968k/8k=103496 blocks. Note that if you've recompiled you may have somehow set block size larger, but installations with postgresql block sizes ~=8k are pretty uncommon, and you'd know if you had done that, so it's probably 8k blocks. ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly