From: Marko Tiikkaja <marko(at)joh(dot)to>
To: Michael Paquier <michael(dot)paquier(at)gmail(dot)com>
Cc: Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org>
Date: 2015-11-22 00:54:51
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On 2015-11-16 08:24, Michael Paquier wrote:
> On Sun, Nov 1, 2015 at 2:49 AM, Marko Tiikkaja <marko(at)joh(dot)to> wrote:
>> Attached is a patch for being able to do $SUBJECT without a CTE. The
>> reasons this is better than a CTE version are:
>> 1) It's not obvious why a CTE version works but a plain one doesn't
>> 2) This one has less overhead (I measured a ~12% improvement on a
>> not-too-unreasonable test case)
> Would you mind sharing this test case as well as numbers?

Attached the test case I used; removing a batch of old rows from a table
through an index. Best out of three runs, I get 13.1 seconds versus
15.0 seconds, which should amount to an improvement of around 12.7%.

Also attached a v3 of the patch which adds an Assert on top of the test
case changes suggested by you.


Attachment Content-Type Size
copy_dml_returning_test.sql text/plain 457 bytes
copy_dml_returning_v3.patch text/x-patch 19.1 KB

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