| From: | panam <panam(at)gmx(dot)net> |
|---|---|
| To: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: [PERFORM] Hash Anti Join performance degradation |
| Date: | 2011-06-01 12:40:55 |
| Message-ID: | 1306932055085-4445123.post@n5.nabble.com |
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| Lists: | pgsql-hackers pgsql-performance |
Tom Lane-2 wrote:
>
> It looks like it ought to be an O(N^2)
> situation, so the improvement should be noticeable but not amazing.
>
Hm, the performance was reasonable again when doing a cluster...
So I believe this should be more a technical than an
algorithmical/complexity issue. Maybe it is the way the hashtable is built
and that order makes a difference in that case? In short: Why is clustered
data not affected?
Regards,
panam
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