Re: Potential Join Performance Issue

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От Lawrence, Ramon
Тема Re: Potential Join Performance Issue
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Msg-id 6EEA43D22289484890D119821101B1DF2C1864@exchange20.mercury.ad.ubc.ca
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Ответ на Re: Potential Join Performance Issue  ("Lawrence, Ramon" <ramon.lawrence@ubc.ca>)
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> Has this been completed?  TODO item?

> > > I'd be more inclined to deal with the issue by trying to establish
a
> > > "safety margin" in the estimate of whether the hash will go
> > multi-batch.
> > > IOW we should disuse_physical_tlist if the hash is estimated to be
> > close to but still within one batch.

I do not know how this issue was resolved.  It is an issue that is very
important for multi-batch hash joins.  The simplest resolution is to
disable physical_tlist on the outer relation for hash joins of more than
one batch.  However, as discussed in the thread, more sophisticated
solutions are also viable.

--
Ramon Lawrence


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