Danny>How much cases are there in production ? This example itself seems very marginalized. I’m not against with it, I’m suspicious about the value of the feature.
It improves JdbcTest#testJoinManyWay 2 times or so. master. JdbcTest#testJoinManyWay: 5.8sec https://travis-ci.org/apache/calcite/jobs/630602718#L1646 with normalization fix: JdbcTest#testJoinManyWay: 3.1sec https://travis-ci.org/apache/calcite/jobs/630719276#L1432 The fix is vital for the proper support of EnumerableMergeJoin as well. If EnumerableMergeJoin is activated, then JdbcTest#testJoinManyWay can't complete within 5 minutes (see PR 1702) Vladimir
