Re: Reduce pinning in btree indexes

From: Kevin Grittner <kgrittn(at)ymail(dot)com>
To: Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>
Cc: "hlinnakangas(at)vmware(dot)com" <hlinnakangas(at)vmware(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Reduce pinning in btree indexes
Date: 2015-03-01 14:08:29
Message-ID: 182394017.537297.1425218909559.JavaMail.yahoo@mail.yahoo.com
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Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote:

> Hello, I measured the performance of this patch considering
> markpos/restorepos. The loss seems to be up to about 10%
> unfortunately.

Thanks for the test case!

I took another look at this optimization, and found that it didn't
really depend on the pin (as I had first thought), so I put it back
(keeping the rest of the patch unchanged). I saw a 1.4% increase
in run time with the patch (compared to master) for the mark-only
test, and a 1.6% increase in run time for the mark/restore test.
I'll look into what might be causing that. I have seen bigger
differences just due to changing where executable code crossed
cache boundaries, but this is big enough to worry about; it needs
to be checked.

New patch attached.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Attachment Content-Type Size
bt-nopin-v2.patch invalid/octet-stream 26.1 KB

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