Re: Seeking performance advice and explanation for high I/O on 8.3

2009/9/3 Scott Otis <scott(dot)otis(at)intand(dot)com>:
> Sorry about not responding to the whole list earlier - this is my first time posting to a mailing list.
>
> Would providing more information about the size and complexities of the databases help?
>
> I measure I/O stats with iostat - here is the command I use:
>
> iostat -d -x mfid0 -t 290 2

Simply do "iostat mfid0 1" and post 10 lines of its output.

> When using 'top -m io' the postgres stats collector process is constantly at 99% - 100%.

In itself it doesn't mean much. The number of IOs is important.

> I don't think my setup is necessarily slow.  I just want to make it as efficient as possible and wanted to get some feedback to see if am setting things up right.  I am also looking out into the future and seeing how much load I can put on this server before getting another one.  If I can reduce the I/O and CPU that the stats collector and autovacuum are using without losing any functionality then I can put more load on the server.

In general it's tricky to optimize for unknown targets - if your
performance is OK right now, you should leave it alone.

On the other hand, your diagnosis of stats collector doing 46 MB/s
points to something very abnormal. You should probably post your
entire postgresql.conf.

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