Re: Turning off transactions completely.

On Tue, Jan 08, 2002 at 11:32:39AM +0530, Arsalan Zaidi wrote:
> I'm vacuuming like crazy (after the initial data COPY and then once the run
> ends(to prepare for the next run)) but there are two issues...

Quick question: you are creating the indices *after* you insert the data,
right?

> 1. VACUUM is dead slow. The CPU monitor shows long stretches when there's
> barely any activity at all while the vacuum is going on.
>
> 2. I do vacuum analyze's to help the database figure out how to best run my
> queries. But it *still* doesnt use some of them...

A vacuum analyze does a vacuum also so you only need to do the former.

> Ah, interesting point. I spent the last two (working) days converting my
> single process app into a multi threaded one, to allow me to fire off
> multiple queries at the same time. I was hoping this would lead to a more
> optimum use of system resources... Didn't work. Best case, the
> multi-threaded app is just as fast as the single -threaded one and in the
> worst case; it's much slower.

Strange, that would indicate a serious bottleneck. Are you saturating the
disks? You can use vmstat to work out the amount of disk activity.

> I'm guessing that the various complex queries being fired at the same time
> are forcing the use of Swap (yes, it on another HDD entirely) ; which is
> slowing down the machine.

You say you had 1 GB of memory? Could you give an example of a query that
uses this amount of memory.

HTH,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org>
http://svana.org/kleptog/
> Terrorists can only take my life. Only my government can take my freedom.