Re: [PERFORM] investigating slow queries through pg_stat_activity

2005-07-03 Thread Enrico Weigelt
* Dan Harris [EMAIL PROTECTED] wrote: Hi, I've got some queries generated by my application that will, for some reason, run forever until I kill the pid. Yet, when I run the queries manually to check them out, they usually work fine. If you can change your application, you could try

[PERFORM] plain inserts and deletes very slow

2005-07-03 Thread Enrico Weigelt
Hi folks, my application reads and writes some table quite often (multiple times per second). these tables are quite small (not more than 20 tuples), but the operations take quite a long time (300 ms!). The query operations are just include text matching (=) and date comparison (,). I

Re: [PERFORM] plain inserts and deletes very slow

2005-07-03 Thread Enrico Weigelt
* Steinar H. Gunderson [EMAIL PROTECTED] wrote: On Mon, Jul 04, 2005 at 12:45:37AM +0200, Enrico Weigelt wrote: my application reads and writes some table quite often (multiple times per second). these tables are quite small (not more than 20 tuples), but the operations take quite a long

Re: [PERFORM] plain inserts and deletes very slow

2005-07-03 Thread Steinar H. Gunderson
On Mon, Jul 04, 2005 at 12:45:37AM +0200, Enrico Weigelt wrote: my application reads and writes some table quite often (multiple times per second). these tables are quite small (not more than 20 tuples), but the operations take quite a long time (300 ms!). Are you VACUUMing often enough? /*

Re: [PERFORM] plain inserts and deletes very slow

2005-07-03 Thread Enrico Weigelt
* Enrico Weigelt [EMAIL PROTECTED] wrote: forgot to mention: + linux-2.6.9 + postgres-7.4.6 + intel celeron 2ghz + intel ultra ata controller + 768mb ram cu -- - Enrico Weigelt== metux IT service

Re: [PERFORM] plain inserts and deletes very slow

2005-07-03 Thread David Mitchell
Did you vacuum full? When you do lots of inserts and deletes, dead tuples get left behind. When you vacuum, postgres will reuse those dead tuples, but if you don't vacuum for a long time these tuples will build up lots. Even when you vacuum in this case, the dead tuples are still there,

Re: [PERFORM] plain inserts and deletes very slow

2005-07-03 Thread Enrico Weigelt
* David Mitchell [EMAIL PROTECTED] wrote: Did you vacuum full? When you do lots of inserts and deletes, dead tuples get left behind. When you vacuum, postgres will reuse those dead tuples, but if you don't vacuum for a long time these tuples will build up lots. Even when you vacuum in

Re: [PERFORM] plain inserts and deletes very slow

2005-07-03 Thread David Mitchell
Perhaps if you are doing a lot of inserts and deletes, vacuuming every 6 minutes would be closer to your mark. Try vacuuming every 15 minutes for a start and see how that affects things (you will have to do a vacuum full to get the tables back into shape after them slowing down as they have).

Re: [PERFORM] plain inserts and deletes very slow

2005-07-03 Thread Enrico Weigelt
* David Mitchell [EMAIL PROTECTED] wrote: Perhaps if you are doing a lot of inserts and deletes, vacuuming every 6 minutes would be closer to your mark. Try vacuuming every 15 minutes for a start and see how that affects things (you will have to do a vacuum full to get the tables back into

Re: [PERFORM] plain inserts and deletes very slow

2005-07-03 Thread Alvaro Herrera
On Mon, Jul 04, 2005 at 02:17:47AM +0200, Enrico Weigelt wrote: * David Mitchell [EMAIL PROTECTED] wrote: Perhaps if you are doing a lot of inserts and deletes, vacuuming every 6 minutes would be closer to your mark. Try vacuuming every 15 minutes for a start and see how that affects

Re: [PERFORM] plain inserts and deletes very slow

2005-07-03 Thread David Mitchell
Hmm, you said you don't experience this when executing the query manually. What adapter are you using to access postgres from your application? libpq, npgsql or something else? And what is your method for running the query 'manually'. Are you running it locally or from a remote machine or