Re: [PATCHES] Last infomask bit - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: [PATCHES] Last infomask bit
Date
Msg-id 45A617F2.6070402@enterprisedb.com
Whole thread Raw
In response to Re: [PATCHES] Last infomask bit  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
>> Tom Lane wrote:
>>> Has anyone bothered to measure the overhead added by having to mask to
>>> fetch or store the natts value?  This is not a zero-cost improvement.
>
>> Tom, how should this be tested?  I assume some loop of the same query
>> over and over again.
>
> I'd be satisfied by a demonstration of no meaningful difference in
> pgbench numbers.

I ran pgbench on CVS checkout taken before the patch was applied, and I
couldn't measure a difference.

I got 1329-1340 TPM from three runs both with and without the patch. The
tests were run on my laptop, with scaling factor 10, using "pgbench
postgres -t 100000 -v", with fsync and full_page_writes disabled to make
it CPU bound, while observing top to confirm that CPU usage was 100%
during the test.

I think that's enough performance testing for this patch.

--
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com

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