Re: Need advice about triggers - Mailing list pgsql-performance

From Mindaugas Riauba
Subject Re: Need advice about triggers
Date
Msg-id 00dc01c376d6$f9f99c30$f20214ac@bite.lt
Whole thread Raw
In response to Need advice about triggers  ("Mindaugas Riauba" <mind@bi.lt>)
Responses Re: Need advice about triggers
Re: Need advice about triggers
List pgsql-performance
> >   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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