Re: pgsql/src/include/optimizer (paths.h planmain.h)

>   Date: Sunday, July 23, 2000 @ 23:10:54
> Author: tgl
>
> Update of /home/projects/pgsql/cvsroot/pgsql/src/include/optimizer
>      from hub.org:/home/projects/pgsql/tmp/cvs-serv74468/include/optimizer
>
> Modified Files:
>     paths.h planmain.h
>
> -----------------------------  Log Message  -----------------------------
>
> Deduce equality constraints that are implied by transitivity of
> mergejoinable qual clauses, and add them to the query quals.  For
> example, WHERE a = b AND b = c will cause us to add AND a = c.
> This is necessary to ensure that it's safe to use these variables
> as interchangeable sort keys, which is something 7.0 knows how to do.
> Should provide a useful improvement in planning ability, too.
>

Hard to imagine this didn't happen before.

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