Re: immutable functions vs. join for lookups ?

From: Tom Lane
Subject: Re: immutable functions vs. join for lookups ?
Date: ,
Msg-id: 25151.1113853826@sss.pgh.pa.us
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In response to: Re: immutable functions vs. join for lookups ?  (Greg Stark)
Responses: Re: immutable functions vs. join for lookups ?  (Enrico Weigelt)
List: pgsql-performance

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immutable functions vs. join for lookups ?  (Enrico Weigelt, )
 Re: immutable functions vs. join for lookups ?  (Tom Lane, )
  Re: immutable functions vs. join for lookups ?  (Enrico Weigelt, )
   Re: immutable functions vs. join for lookups ?  (Jaime Casanova, )
    Re: immutable functions vs. join for lookups ?  (Enrico Weigelt, )
     Re: immutable functions vs. join for lookups ?  (Dawid Kuroczko, )
 Re: immutable functions vs. join for lookups ?  (Dawid Kuroczko, )
 Re: immutable functions vs. join for lookups ?  ("Merlin Moncure", )
  Re: immutable functions vs. join for lookups ?  (Dawid Kuroczko, )
   Re: immutable functions vs. join for lookups ?  ("Jim C. Nasby", )
    Re: immutable functions vs. join for lookups ?  (Dawid Kuroczko, )
     Re: immutable functions vs. join for lookups ?  (Christopher Kings-Lynne, )
     Re: immutable functions vs. join for lookups ?  (Christopher Kings-Lynne, )
  Re: immutable functions vs. join for lookups ?  (Tom Lane, )
   Re: immutable functions vs. join for lookups ?  (Greg Stark, )
    Re: immutable functions vs. join for lookups ?  (Tom Lane, )
     Re: immutable functions vs. join for lookups ?  (Enrico Weigelt, )
      Re: immutable functions vs. join for lookups ?  (Dawid Kuroczko, )

Greg Stark <> writes:
> Tom Lane <> writes:
>> It would be interesting sometime to try to teach the planner about
>> inlining SQL-language functions to become joins.  That is, given

> The Inlining of the function is presumably a side-issue. I have tons of
> queries that use subqueries in the select list for which the same behaviour
> would be appropriate.

Yeah, I was actually thinking about a two-step process: inline the
function to produce somethig equivalent to a handwritten scalar
sub-SELECT, and then try to convert sub-SELECTs into joins.

            regards, tom lane


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