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Re: Seq Scan used instead of Index Scan - Mailing list pgsql-performance

From Claudio Freire
Subject Re: Seq Scan used instead of Index Scan
Date
Msg-id CAGTBQpbaW_PQf-3bH5Xc6x9SSAawNsUUBRMESkRz8AKTqZ96fQ@mail.gmail.com
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In response to Seq Scan used instead of Index Scan  (Gary Warner <gar@cis.uab.edu>)
List pgsql-performance
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On Wed, Nov 23, 2011 at 7:24 PM, Gary Warner <gar@cis.uab.edu> wrote:
> See that "Seq Scan on link_url"?  We can't figure out why that is there!  We should be scanning for a matching
"urlid"and we have an index on "urlid"? 
>
> When this is happening in a "two table" version of this problem, we can get temporary relief by giving the statement:
>
> set enable_seqscan = false;

Obviously, because it thinks the index scan will perform worse.

It would be interesting to see the explain analyze with
enable_seqscan=false to see why

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