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Re: When can postgresql use a partial (NOT NULL) index? Seems to depend on size of IN clause (even with enable seqscan = off) - Mailing list pgsql-general

From Scott Marlowe
Subject Re: When can postgresql use a partial (NOT NULL) index? Seems to depend on size of IN clause (even with enable seqscan = off)
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Msg-id AANLkTi=wmUTgZY5fvGjuiDpG1L==pJkc_BQW_KrdL1s9@mail.gmail.com
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In response to When can postgresql use a partial (NOT NULL) index? Seems to depend on size of IN clause (even with enable seqscan = off)  (Timothy Garnett <tgarnett@panjiva.com>)
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On Tue, Aug 3, 2010 at 2:03 PM, Timothy Garnett <tgarnett@panjiva.com> wrote:
> Hi all,
>
> I'm debugging a performance issue that looks like it might actually be an
> issue/limitation/parameter/bug in the query planner, but since I couldn't
> find anything authoritative on when exactly postgresql is able to use
> partial not null indexes I'm not sure that that's the case and I was hopping
> someone could give some clarity around that or point to an option I could
> tweak that would change this behavior.  Anyways the table in question (with
> names changed) is below.  I'm running postgres 8.4.1

8.4.1 has some pretty nasty bugs that have since been fixed, and some
work was done on the planner as well since then.  First upgrade and
see if your problem goes away.

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