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Message-ID: <4BBD3A17.90209@emolecules.com>
Date: Wed, 07 Apr 2010 19:06:15 -0700
From: Craig James <craig_james@emolecules.com>
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To: Robert Haas <robertmhaas@gmail.com>
CC: David Rees <drees76@gmail.com>, pgsql-performance@postgresql.org
Subject: Re: Occasional giant spikes in CPU load
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On 4/7/10 5:47 PM, Robert Haas wrote:
> On Wed, Apr 7, 2010 at 6:56 PM, David Rees<drees76@gmail.com>  wrote:
>>> max_fsm_pages = 16000000
>>> max_fsm_relations = 625000
>>> synchronous_commit = off
>>
>> You are playing with fire here.  You should never turn this off unless
>> you do not care if your data becomes irrecoverably corrupted.
>
> That is not correct.  Turning off synchronous_commit is sensible if
> you don't mind losing the last few transactions on a crash.  What will
> corrupt your database is if you turn off fsync.

A bit off the original topic, but ...

I set it this way because I was advised that with a battery-backed RAID controller, this was a safe setting.  Is that not the case?

Craig