Re: BUG #8598: Row count estimates of partial indexes - Mailing list pgsql-bugs

From Tom Lane
Subject Re: BUG #8598: Row count estimates of partial indexes
Date
Msg-id 16493.1384719519@sss.pgh.pa.us
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In response to Re: BUG #8598: Row count estimates of partial indexes  (Marko Tiikkaja <marko@joh.to>)
Responses Re: BUG #8598: Row count estimates of partial indexes  (Marko Tiikkaja <marko@joh.to>)
List pgsql-bugs
Marko Tiikkaja <marko@joh.to> writes:
> Any suggestions for a workaround?  When reading this index as a part of
> a bigger query the horrible estimate ensures that nobody's having fun.

Why is the estimate so bad?  I suppose the answer is that those two
columns are very strongly correlated.  Maybe you could refactor your
data representation to avoid that?

The long-term answer as far as Postgres is concerned is to learn about
cross-column correlations, but that's not happening in the near future.

            regards, tom lane

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