If you've created your own metadata provider you will need to add an extra RelMetadataQuery mq argument to each method, per CALCITE-794. This was mentioned in the release notes, http://calcite.apache.org/docs/history.html#v1-6-0.

I created a pull request at https://github.com/apache/calcite/pull/193.
Julian please kindly review it.

Julian Hyde thanks for looking into this.

RelDistribute can be a pluggable metadata, however, it is used in Logical RelNodes like LogicalFilter, which is deeply coupled with multiple rules and utilities. It is highly recommended that we fix this bug in calcite-core.

Ah, I see now. The other way of way of stating this bug is: RelMdDistribution is not tested. If there were a test, the assert would have shown up. Do you feel like adding a test to RelMetadataTest? (I don't think the test in your patch exercises the metadata provider, so it won't exercise this bug.)

Thanks Julian Hyde, that's exactly what I'm expecting, but I'm not sure if adding RelMdDistribution into default metadata provider could have other impact.

I'm added RelMdDistribution into default metadata provider, the updated pull request is https://github.com/apache/calcite/pull/194. We can also add RelMdDistribution into RelMetadataTest only, if you feel the former way is too intrusive.

I think it's fine to add RelMdDistribution to DefaultRelMetadataProvider.

I'd also like to add a test or two to RelMetadataTest. Neither of your branches seem to have modified RelMetadataTest; is that what you intended?

Thanks Julian Hyde.

The pull request is updated.

Fixed in http://git-wip-us.apache.org/repos/asf/calcite/commit/4dfd6dbb. Thanks for the PR, Ted Xu!

Resolved in release 1.7.0 (2016-03-22).