Re: [PATCHES] Merge join performance - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [PATCHES] Merge join performance
Date
Msg-id 27586.1156382559@sss.pgh.pa.us
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List pgsql-hackers
Heikki Linnakangas <heikki@enterprisedb.com> writes:
> We can make markpos fast, if we make the copy lazily in _bt_steppage,

Nice hack.  Getting rid of the buffer refcount manipulations is probably
even more useful than avoiding the memcpy.

> I did some micro-benchmarking of merge join performance, see attached
> test. Test results, on my laptop:

> 8_1_STABLE: 1.77 s
> HEAD, with patch: 1.65 s
> HEAD, without patch: 2.46 s

Hm, I don't see a performance regression on my machine, but there is a
measureable improvement with the patch:

8.1 branch:    10.6 s
CVS HEAD:    10.1 s
w/patch:     9.3 s

Patch applied ...

            regards, tom lane

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