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pgsql: Fix thinko in new match_join_clauses_to_index() logic.

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: pgsql-committers(at)postgresql(dot)org
Subject: pgsql: Fix thinko in new match_join_clauses_to_index() logic.
Date: 2012-02-28 23:10:52
Message-ID: E1S2WC4-0003Pp-KI@gemulon.postgresql.org (view raw or flat)
Thread:
Lists: pgsql-committers
Fix thinko in new match_join_clauses_to_index() logic.

We don't need to constrain the other side of an indexable join clause to
not be below an outer join; an example here is

SELECT FROM t1 LEFT JOIN t2 ON t1.a = t2.b LEFT JOIN t3 ON t2.c = t3.d;

We can consider an inner indexscan on t3.d using c = d as indexqual, even
though t2.c is potentially nulled by a previous outer join.  The comparable
logic in orindxpath.c has always worked that way, but I was being overly
cautious here.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/0140a11b9ba5b22e1e4807e178bca770d46c3e28

Modified Files
--------------
src/backend/optimizer/path/indxpath.c |    8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)

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