Thanks Julian. I looked in the existing rules but didn't come across the ReduceExpressionsRule.FILTER_INSTANCE. Adding that rule to the planner seems to do the same thing that I was trying to do in simplify. I don't think there is any reason to change simplify. It was just the first way to found to try to work around the issue I was facing.
Would you still want a JIRA case logged since that would result in multiple ways of doing the same thing? Kevin Risden On Sun, Feb 19, 2017 at 8:13 PM, Julian Hyde <[email protected]> wrote: > We have support for this in planner rules -- I’m pretty sure that > ReduceExpressionsRule.FILTER_INSTANCE will convert ‘where 1 = 0’ to > ‘where false’, then PruneEmptyRules.FILTER_INSTANCE will make the Filter > disappear altogether — but arguably it could happen in RexUtil.simplify > also. > > The purpose of RexUtil.simplify is to simplify (only) patterns that are > commonly occurring, easy to recognize, and will produce a quick win in > terms of the size of the RelNode/RexNode tree. I don’t know yet whether > this passes that threshold. Can you log a JIRA case for this and we can > discuss further? > > By the way, https://issues.apache.org/jira/browse/CALCITE-1638 < > https://issues.apache.org/jira/browse/CALCITE-1638> is related. It > changed the result of a test that was doing ‘where 1 = 1’. > > Julian > > > > > > On Feb 19, 2017, at 2:03 PM, Kevin Risden <[email protected]> > wrote: > > > > While working on Solr and Calcite integration, I found that there is a > case > > where some tools issue a sql query like "where 1 = 0" just to get > metadata > > information back. Spark SQL is one of the ones that does this. > > > > Calcite doesn't seem to optimize away the literal comparison literal case > > with RexUtil.simplify. In my understanding any literal comparison literal > > results in a simple TRUE/FALSE result. > > > > I'm not sure this is valid in the general case, but I put together a > simple > > example of doing this on the RexUtil simplifyCall. > > > > https://github.com/apache/calcite/pull/376 > > > > I would love to hear any feedback related to this. I need to run through > > the full Calcite test suite, but wondering if this is even viable. > > > > Thanks! > > > > Kevin Risden > >
