From: Greg Smith <greg@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Eduardo Piombino <drakorg@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: a heavy duty operation on an "unused" table kills my server
Date: Wed, 13 Jan 2010 13:46:03 -0500
Message-ID: <4B4E14EB.7080008@2ndquadrant.com> (raw)
In-Reply-To: <603c8f071001130823l69804fe3m5c6fbb081c55c265@mail.gmail.com>
References: <e24c1d9d1001122059ic5d4721o98ccf85033b1fead@mail.gmail.com>
<4B4D5698.8040808@emolecules.com>
<e24c1d9d1001122147l1c0e2111kce25dc2c7f393087@mail.gmail.com>
<4B4D61DA.7080008@postnewspapers.com.au>
<e24c1d9d1001122303g1d4eea48h18bd73467d1fa8ec@mail.gmail.com>
<603c8f071001130823l69804fe3m5c6fbb081c55c265@mail.gmail.com>
Robert Haas wrote:
> I'm kind of surprised that there are disk I/O subsystems that are so
> bad that a single thread doing non-stop I/O can take down the whole
> server. Is that normal? Does it happen on non-Windows operating
> systems? What kind of hardware should I not buy to make sure this
> doesn't happen to me?
>
You can kill any hardware on any OS with the right abusive client.
Create a wide table and insert a few million records into it with
generate_series one day and watch what it does to queries trying to run
in parallel with that.
I think the missing step here to nail down exactly what's happening on
Eduardo's system is that he should open up some of the Windows system
monitoring tools, look at both disk I/O and CPU usage, and then watch
what changes when the troublesome ALTER TABLE shows up.
--
Greg Smith 2ndQuadrant Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com www.2ndQuadrant.com
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To: pgsql-performance@postgresql.org
Cc: greg@2ndquadrant.com, robertmhaas@gmail.com, drakorg@gmail.com
Subject: Re: a heavy duty operation on an "unused" table kills my server
In-Reply-To: <4B4E14EB.7080008@2ndquadrant.com>
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