Re: slow update of index during insert/copy

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On Tue, 2 Sep 2008, Thomas Finneid wrote:

You should try setting this to open_sync , that can be considerably faster for some write-heavy situations. Make sure to test that throughly though, there are occasional reports of issues with that setting under Linux

The production machine is Solaris 10 running on a Sun v980. Do you know of it has any issues like these?

On Solaris you can safely use open_datasync which is a bit better than open_sync. For best results, you need to separate the xlog onto a separate partition and mount it using forcedirectio, because Postgres doesn't know how to use direct I/O directly on Solaris yet.

Additionally, would I need to do any config changes when going from linux to solaris?

Assuming the same amount of memory, the postgresql.conf should be basically the same, except for the wal_sync_method change mentioned above. If there's more RAM in the production server you can ramp up shared_buffers, effective_cache_size, and possibly work_mem proportionately. The settings I suggested for maintenance_work_mem and wal_buffers are already near the useful upper limits for those parameters.

There are a few operating system level things you should consider tweaking on Solaris 10 for better PostgreSQL performance. You need to be a bit more careful about the parameters used for the filesystem than on Linux, and the settings there vary considerably depending on whether you're using UFS or ZFS. The best intro to that I know of is at http://blogs.sun.com/jkshah/entry/postgresql_east_2008_talk_best ; I added some clarification to a few points in there and some other Solaris notes at http://notemagnet.blogspot.com/2008_04_01_archive.html Those should get you started.

I hope you're already looking into some sort of repeatable benchmarking that's representative of your application you can run. You'll go crazy playing with all these settings without something like that.

--
* Greg Smith gsmith@xxxxxxxxxxxxx http://www.gregsmith.com Baltimore, MD


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