< 		o Fix memory leak from exceptions
<
< 		  http://archives.postgresql.org/pgsql-performance/2006-06/msg00305.php
<
< * Allow constraint_exclusion to work for UNIONs like it does for
<   inheritance, allow it to work for UPDATE and DELETE statements, and allow
<   it to be used for all statements with little performance impact
<
< * Add estimated_count(*) to return an estimate of COUNT(*)
<
<   This would use the planner ANALYZE statistics to return an estimated
<   count.
<   http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php