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Re: [GENERAL] Equivalence Classes when using IN - Mailing list pgsql-general

From Kim Rose Carlsen
Subject Re: [GENERAL] Equivalence Classes when using IN
Date
Msg-id 00313177-8506-43BC-9F6B-2C19F0E5A98B@hiper.dk
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In response to Re: [GENERAL] Equivalence Classes when using IN  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: [GENERAL] Equivalence Classes when using IN
List pgsql-general
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> Yeah.  The ORDER BY creates a partial optimization fence, preventing
> any such plan from being considered.
>>

I can see in the general case it semanticly means different things If you allow the WHERE to pass through ORDER BY.

A special case can be allowed for WHERE to pass the ORDER BY if the column is part of DISTINCT ON.




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