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pgsql: Adjust join_search_one_level's handling of clauseless joins.

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: pgsql-committers(at)postgresql(dot)org
Subject: pgsql: Adjust join_search_one_level's handling of clauseless joins.
Date: 2012-04-21 00:11:48
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-committers
Adjust join_search_one_level's handling of clauseless joins.

For an initial relation that lacks any join clauses (that is, it has to be
cartesian-product-joined to the rest of the query), we considered only
cartesian joins with initial rels appearing later in the initial-relations
list.  This creates an undesirable dependency on FROM-list order.  We would
never fail to find a plan, but perhaps we might not find the best available
plan.  Noted while discussing the logic with Amit Kapila.

Improve the comments a bit in this area, too.

Arguably this is a bug fix, but given the lack of complaints from the
field I'll refrain from back-patching.



Modified Files
src/backend/optimizer/path/joinrels.c |   46 +++++++++++++++++++-------------
1 files changed, 27 insertions(+), 19 deletions(-)

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Subject: pgsql: Recast "ONLY" column CHECK constraints as NO INHERIT
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Subject: pgsql: Revise parameterized-path mechanism to fix assorted issues.

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