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Why could GEQO produce plans with lower costs than thestandard_join_search? - Mailing list pgsql-hackers

From Donald Dong
Subject Why could GEQO produce plans with lower costs than thestandard_join_search?
Date
Msg-id 5A76B3F6-200F-4721-94E9-9C377F582568@csumb.edu
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Responses Re: Why could GEQO produce plans with lower costs than the standard_join_search?  (Tom Lane <tgl@sss.pgh.pa.us>)
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Hi,

I was expecting the plans generated by standard_join_search to have lower costs
than the plans from GEQO. But after the results I have from a join order
benchmark show that GEQO produces plans with lower costs most of the time!

I wonder what is causing this observation? From my understanding,
standard_join_search is doing a complete search. So I'm not sure how the GEQO
managed to do better than that.

Thank you,
Donald Dong

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