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Re: [COMMITTERS] pgsql: If we expect a hash join to be performed in multiple batches, - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: [COMMITTERS] pgsql: If we expect a hash join to be performed in multiple batches,
Date
Msg-id 1238692283.5444.123.camel@ebony.2ndQuadrant
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Responses Re: [COMMITTERS] pgsql: If we expect a hash join to be performed in multiple batches,  (Tom Lane <tgl@sss.pgh.pa.us>)
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On Thu, 2009-03-26 at 17:15 +0000, Tom Lane wrote:
> Log Message:
> -----------
> If we expect a hash join to be performed in multiple batches, suppress
> "physical tlist" optimization on the outer relation (ie, force a projection
> step to occur in its scan).  This avoids storing useless column values when
> the outer relation's tuples are written to temporary batch files.

Can we add "batches=N" to the EXPLAIN output for Hash and/or Hash Join?

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support

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