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Re: OOM Errors as a result of table inheritance and a bad plan(?) - Mailing list pgsql-performance

From Tom Lane
Subject Re: OOM Errors as a result of table inheritance and a bad plan(?)
Date
Msg-id 19037.1191013009@sss.pgh.pa.us
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In response to OOM Errors as a result of table inheritance and a bad plan(?)  (Arctic Toucan <arctic_toucan@hotmail.com>)
List pgsql-performance
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Arctic Toucan <arctic_toucan@hotmail.com> writes:
> -- Is there something magical about the hash aggregate estimate of 200 rows?

Yeah, it's the default :-(

> Is this a bug, or some subtlety of the Postgres query planner?

It's an, um, known deficiency --- the planner hasn't got any idea how to
construct aggregated statistics for an inheritance tree.

            regards, tom lane

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