Re: Need advice about triggers

From: "Mindaugas Riauba" <mind(at)bi(dot)lt>
To: <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Need advice about triggers
Date: 2003-09-09 13:33:32
Message-ID: 00dc01c376d6$f9f99c30$f20214ac@bite.lt
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> > How can I improve performance and will version 7.4 bring something
> > valuable for my task? Rewrite to some other scripting language is not
> > a problem. Trigger is simple enough.
>
> Well, try it without the trigger. If performance improves markedly, it
might
> be worth rewriting in C.

Nope. Execution time is practically the same without trigger.

> If not, you're probably saturating the disk I/O - using iostat/vmstat will
let
> you see what's happening. If it is your disks, you might see if moving the
> WAL onto a separate drive would help, or check the archives for plenty of
> discussion about raid setups.

Bottleneck in this case is CPU. postmaster process uses almost 100% of
CPU.

> > Postgres v7.3.4, shared_buffers=4096 max_fsm settings also bumped up
> > 10 times.
> Well effective_cache_size is useful for reads, but won't help with
writing.
> You might want to look at wal_buffers and see if increasing that helps,
but I
> couldn't say for sure.

Disk I/O should not be a problem in this case. vmstat shows ~300kb/s write
activity.

Mindaugas

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