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Subject: Re: incorrect row estimates for primary key join
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From: Ben <midfield@gmail.com>
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Date: Wed, 26 Jun 2013 20:48:16 -0700
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Kevin Grittner <kgrittn@ymail.com>,
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On Jun 26, 2013, at 5:22 PM, Marcin Ma=C5=84k wrote:

> On Wed, Jun 26, 2013 at 2:29 AM, Ben <midfield@gmail.com> wrote:
>=20
>> shouldn't an index scan definitely be fastest here?  you don't need to t=
ouch the whole table or index.  maybe there something i have misconfigured =
here?
>>=20
>=20
> How about you try increasing work_mem ? I think a hash join may be the
> best plan here, and it won't get chosen with low work_mem .

i will increase work_mem and experiment for the other queries, but the quer=
y which i was asking about in this particular question was looking up the s=
ingle smallest key in the primary key index, which seems like it shouldn't =
need to touch more than one key, since it can just get the first one from a=
n in-order index traversal.  of course with my earlier bigtable/jointable j=
oin question increasing work_mem makes a lot of sense.

best regards, ben



--=20
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