Re: Deferred constraints performance impact ? - Mailing list pgsql-performance

From Robert Klemme
Subject Re: Deferred constraints performance impact ?
Date
Msg-id CAM9pMnMinr95msZ7JV2LP6sEJsvNDdXttRUhdfVp1YC5ziPkUA@mail.gmail.com
Whole thread Raw
In response to Deferred constraints performance impact ?  ("mark" <dvlhntr@gmail.com>)
List pgsql-performance
On Fri, Jul 20, 2012 at 4:27 AM, mark <dvlhntr@gmail.com> wrote:
> We have put some deferred constraints (some initially immediate, some
> initially deferred) into our database for testing with our applications.

> 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.

Another factor might be the amount of constraint violations you
expect: if there are many then deferring the check can create much
more work for the DB because you issue more DML as with a non deferred
constraint which could create errors much sooner and hence make you
stop sending DML earlier.

Kind regards

robert


--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/


pgsql-performance by date:

Previous
From: David Barton
Date:
Subject: Re: Postgres 9.1.4 - high stats collector IO usage
Next
From: Jeff Janes
Date:
Subject: Re: Postgres 9.1.4 - high stats collector IO usage