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Message-ID: <1344811330.19209.27.camel@jdavis>
Subject: Re: Deferred constraints performance impact ?
From: Jeff Davis <pgsql@j-davis.com>
To: mark <dvlhntr@gmail.com>
Cc: pgsql-performance@postgresql.org
Date: Sun, 12 Aug 2012 15:42:10 -0700
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On Thu, 2012-07-19 at 20:27 -0600, mark wrote:
> I understand a lot more may have to be tracked through a transaction and
> there could be some impact from that. Similar to an after update trigger? Or
> are the two not comparable in terms of impact from what is tracked and then
> checked. 

They should be very comparable to AFTER triggers. It's actually a little
better because there are optimizations to avoid queuing constraint
checks if we know it will pass.

I would recommend testing a few degenerate cases to see how big the
impact is, and try to see if that is reasonable for your application.

Regards,
	Jeff Davis