Re: fine tuning for logging server

Florin Andrei wrote:

>On Wed, 2005-03-30 at 17:50 -0800, Florin Andrei wrote:
>
>
>
>>Function: Essentially a logging server. There are two applications (like
>>syslog) on the same box that are logging to pgsql, each one to its own
>>database. There are a few tables in one DB, and exactly one table in the
>>other.
>>Most of the time, the apps are just doing mindless INSERTs to the DB.
>>Every now and then, an admin performs some SELECTs via a PHP interface.
>>
>>
>
>For performance reasons, i was thinking to keep the tables append-only,
>and simply rotate them out every so often (daily?) and delete those
>tables that are too old. Is that a good idea?
>
>
>
If you aren't doing updates, then I'm pretty sure the data stays packed
pretty well. I don't know that you need daily rotations, but you
certainly could consider some sort of rotation schedule.

The biggest performance improvement, though, is probably to group
inserts into transactions.
I had an application (in a different db, but it should be relevant),
where using a transaction changed the time from 6min -> 6 sec.
It was just thrashing on all the little inserts that it had to fsync to
disk.

How fast is fast? How many log messages are you expecting? 1/s 100/s 1000/s?
I think the hardware should be capable of the 10-100 range if things are
properly configured. Naturally that depends on all sorts of factors, but
it should give you an idea.

John
=:->