Re: Understanding Hash Join performance

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On Thu, Jun 2, 2011 at 4:57 PM, Kevin Grittner
<Kevin.Grittner@xxxxxxxxxxxx> wrote:
> And the
> planner does take the size of work_mem and the expected data set
> into consideration when estimating the cost of the hash join.

And shouldn't it?

In a gross mode, when hash joins go to disk, they perform very poorly.
Maybe the planner should take that into account.

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