| From: | Jeff Davis <pgsql(at)j-davis(dot)com> |
|---|---|
| To: | Gregory Stark <stark(at)enterprisedb(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Kenneth Marshall <ktm(at)rice(dot)edu>, pgsql-hackers(at)postgresql(dot)org, pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: [PATCHES] updated hash functions for postgresql v1 |
| Date: | 2009-01-10 19:07:18 |
| Message-ID: | 1231614438.25019.122.camel@jdavis |
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| Lists: | pgsql-hackers |
On Sat, 2009-01-10 at 13:57 -0500, Gregory Stark wrote:
> But I gather it's a 6% speedup in the time spent actually in the
> hash function.
That's correct. I was not able to detect any difference at all between
the old and new code using HashAggregate, which is where most of my
testing effort went:
http://archives.postgresql.org/message-id/1231531455.25019.75.camel@jdavis
(see test results attached to that message, if you're interested)
I tested with two data distributions and 6 data types.
The 6-10% speedup I saw was a super-micro benchmark testing the hash
function, and I didn't spend much time with that.
Regards,
Jeff Davis
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