pgsql: Fix a pair of related issues with estimation of inequalities that - Mailing list pgsql-committers

Log Message:
-----------
Fix a pair of related issues with estimation of inequalities that involve
binary-compatible relabeling of one or both operands.  examine_variable
should avoid stripping RelabelType from non-variable expressions, so that
they will continue to have the correct type; and convert_to_scalar should
just use that type and ignore the other input type.  This isn't perfect
but it beats failing entirely.  Per example from Michael Fuhr.

Modified Files:
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    pgsql/src/backend/utils/adt:
        selfuncs.c (r1.173 -> r1.174)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/selfuncs.c.diff?r1=1.173&r2=1.174)