A beta-tester has found another bug in the reason query optimizer enhancements!
One of the changes in version 3.23.0 is that the push-down
optimization  was made more aggressive. In other words, the
conditions on which the push-down optimization depended were relaxed
somewhat so that it applies in more situations. In once case, the
optimization went too far and generated a query that did not produce
the same answer. The problem has now been fixed on trunk  and a
new pre-release snapshot has been uploaded . We are continuing to
study the problem to try to think of new ways to break this
So, there have now been two cases during this release cycle where
beta-testers have found obscure cases where an over-eager query
optimization resulted in an incorrect answer. Thank you testers!
We are currently in "pencils down" for the 3.23.0 release cycle. No
new features or enhancements - only bug fixes from here on out. We
will start release testing soon.
So if you have not yet downloaded and tested a pre-release snapshot,
please do so sooner rather than later. This is especially true if you
run complex queries that use lots of views, subqueries, and LEFT
JOINs. Report any problems or concerns to this mailing list, or
directly to me.