From: Eduardo Piombino <drakorg@gmail.com>
To: Greg Smith <greg@2ndquadrant.com>
Cc: Robert Haas <robertmhaas@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 16:13:20 -0300
Message-ID: <e24c1d9d1001131113x69d2f10anbee2c87dbd9856c4@mail.gmail.com> (raw)
In-Reply-To: <4B4E14EB.7080008@2ndquadrant.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>
<4B4E14EB.7080008@2ndquadrant.com>
Greg, I will post more detailed data as soon as I'm able to gather it.
I was trying out if the cancellation of the ALTER cmd worked ok, I might
give the ALTER another try, and see how much CPU, RAM and IO usage gets
involved. I will be doing this monitoring with the process explorer from
sysinternals, but I don't know how I can make it to log the results. Do you
know any tool that you have used that can help me generate this evidence? I
will google a little as soon as possible.
On Wed, Jan 13, 2010 at 3:46 PM, Greg Smith <greg@2ndquadrant.com> wrote:
> 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: drakorg@gmail.com, greg@2ndquadrant.com, robertmhaas@gmail.com
Subject: Re: a heavy duty operation on an "unused" table kills my server
In-Reply-To: <e24c1d9d1001131113x69d2f10anbee2c87dbd9856c4@mail.gmail.com>
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