Re: [PERFORM] Need Some Suggestions
Lane Van Ingen wrote: I have an application that is prone to sudden, unscheduled high bursts of activity, and I am finding that the application design permits me to detect the activity bursts within an existing function. The bursts only affect 3 tables, but degradation becomes apparent after 2,000 updates, and significant after 8,000 updates. Hmm - assuming your free-space settings are large enough, it might be adequate to just run a vacuum on the 3 tables every 5 minutes or so. It sounds like these are quite small tables with a lot of activity, so if there's not much for vacuum to do it won't place too much load on your system. -- Richard Huxton Archonet Ltd ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [PERFORM] Need Some Suggestions
You are correct, in that these tables are not large (50,000 records), but their effect on performance is noticeable. Plain VACUUM (no freeze, full, etc) does the trick well, but I am unable to figure a way to call the 'plain vanilla version' of VACUUM via a PostgreSQL trigger function (does not allow it). Using the Windows scheduler (schtask, somewhat like Unix cron) is an option, but not a good one, as it takes too much out of the platform to run. My client does not use strong platforms, so I have to be concerned about that. VACUUM is a minimum impact on performance when running. I believe it would be much better to be able to call VACUUM out of a function, the same way in which other SQL commands are used. -Original Message- From: Richard Huxton [mailto:[EMAIL PROTECTED] Sent: Friday, October 07, 2005 3:53 AM To: Lane Van Ingen Cc: pgsql-performance@postgresql.org Subject: Re: [PERFORM] Need Some Suggestions Lane Van Ingen wrote: I have an application that is prone to sudden, unscheduled high bursts of activity, and I am finding that the application design permits me to detect the activity bursts within an existing function. The bursts only affect 3 tables, but degradation becomes apparent after 2,000 updates, and quite significant after 8,000 updates. Hmm - assuming your free-space settings are large enough, it might be adequate to just run a vacuum on the 3 tables every 5 minutes or so. It sounds like these are quite small tables with a lot of activity, so if there's not much for vacuum to do it won't place too much load on your system. -- Richard Huxton Archonet Ltd ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
[PERFORM] Need Some Suggestions
I have an application that is prone to sudden, unscheduled high bursts of activity, and I am finding that the application design permits me to detect the activity bursts within an existing function. The bursts only affect 3 tables, but degradation becomes apparent after 2,000 updates, and significant after 8,000 updates. I already know that a plain vacuum (without full, analyze, or free options) solves my problem. Since vacuum is classified in the documentation as an SQL command, I tried to call it using a trigger function on one the tables (they all have roughly the same insert / update rate). However, I just found out that vacuum cannot be called by a function. Vacuums done by a scheduler at 3AM in the morning are adequate to handle my non-peak needs otherwise. autovacuum sounds like it would do the trick, but I am on a WINDOWS 2003 environment, but I have Googled up messages that it still has various problems (in Windows) which won't be resolved until 8.1 is out. But I have a problem NOW, and the application is deployed around the world. QUESTION: Is there anyway anyone knows of to permit me to execute an operating system program (even vacuumdb) or possibly to add a C function to the library which would allow me to do this (I am not a C programmer, but have access to some persons who are)? Very important to me for performance reasons. Does anybody have some suggestions on the best path for me to take? ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
