Re: can't get rid of unnesesary SORT step in explain plan for hash join

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: alexey(at)price(dot)ru
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: can't get rid of unnesesary SORT step in explain plan for hash join
Date: 2001-05-13 01:53:56
Message-ID: 22028.989718836@sss.pgh.pa.us
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Alexey Nalbat <alexey(at)price(dot)ru> writes:
> So, my question is: how can I get rid of this unnesesary "Sort" step
> in the execution plan for hash join?

You can't, because it's not unnecessary. Hash join doesn't promise
to produce its outputs in any particular order. But the Unique
filter needs to see its inputs in order by the fields being made
unique.

regards, tom lane

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