Thread: pgsql: Fix set_joinrel_size_estimates() to estimate outer-join sizes

Log Message:
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Fix set_joinrel_size_estimates() to estimate outer-join sizes more
accurately: we have to distinguish the effects of the join's own ON
clauses from the effects of pushed-down clauses.  Failing to do so
was a quick hack long ago, but it's time to be smarter.  Per example
from Thomas H.

Modified Files:
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    pgsql/src/backend/optimizer/path:
        costsize.c (r1.167 -> r1.168)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/path/costsize.c.diff?r1=1.167&r2=1.168)