Re: DELETE vs TRUNCATE explanation - Mailing list pgsql-performance

From Jeff Janes
Subject Re: DELETE vs TRUNCATE explanation
Date
Msg-id CAMkU=1x36-xLdUORNZCXZh4yt+qC0z+Qqcyj7Y-gfPgFt2w2FA@mail.gmail.com
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In response to Re: DELETE vs TRUNCATE explanation  ("Harold A. Giménez" <harold.gimenez@gmail.com>)
List pgsql-performance
On Thu, Jul 12, 2012 at 4:21 PM, Harold A. Giménez
<harold.gimenez@gmail.com> wrote:
> Hi,
>
> I work with Daniel Farina and was the other engineer who "discovered" this,
> once again. That is, I got bit by it and have been running TRUNCATE on my
> test suites for years.

Hi Daniel and Harold,

I don't know if you followed this thread over into the -hacker mailing list.

There was some bookkeeping code that was N^2 in the number of
truncations performed during any given checkpoint cycle.  That has
been fixed in 9.2Beta3.

I suspect that this was the root cause of the problem you encountered.

If you are in a position to retest using 9.2Beta3
(http://www.postgresql.org/about/news/1405/), I'd be interested to
know if it does make truncations comparable in speed to unqualified
deletes.

Thanks,

Jeff

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