From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Neil Conway <neilc(at)samurai(dot)com> |
Cc: | PostgreSQL Patches <pgsql-patches(at)postgresql(dot)org> |
Subject: | Re: improve join_collapse_limit docs |
Date: | 2004-01-27 06:40:21 |
Message-ID: | 12168.1075185621@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-patches |
Mostly nit-picking, but for what it's worth:
Neil Conway <neilc(at)samurai(dot)com> writes:
> ! <note>
> ! <para>
> ! The order of outer joins specified via the <literal>JOIN</>
> ! construct is never adjusted by the query planner; therefore,
> ! <varname>join_collapse_limit</> has no effect on this
> ! behavior.
This should include some weasel-wording along the lines of "At present,
blah blah blah". It is theoretically legal to reorder outer joins in
some cases, and I harbor ambitions of teaching the planner about that
sooner or later.
> ! <varname>from_collapse_limit</varname>, which is appropriate
> ! for most users. Setting it to 1 prevents any reordering of
"most uses", perhaps ?
> ! order they desire explicitely. Another consequence of setting
spell-check ...
> ! this variable to 1 is that the query planner will behave more
> ! similarly to the <productname>PostgreSQL</productname> 7.3
"more similarly" is bad grammar ... try "more like the" ...
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Patrick Samson | 2004-01-27 09:03:42 | Re: pltcl - "Cache lookup for attribute" error - version 2 |
Previous Message | Neil Conway | 2004-01-27 05:02:48 | improve join_collapse_limit docs |