| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | pgsql-hackers(at)postgresql(dot)org, Heikki Linnakangas <heikki(at)enterprisedb(dot)com> |
| Cc: | pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: Merge join performance |
| Date: | 2006-08-24 01:22:39 |
| Message-ID: | 27586.1156382559@sss.pgh.pa.us |
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| Lists: | pgsql-hackers pgsql-patches |
Heikki Linnakangas <heikki(at)enterprisedb(dot)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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