Hi, I found there are some RelCompositeTrait related issues: https://issues.apache.org/jira/browse/CALCITE-2010 https://issues.apache.org/jira/browse/CALCITE-2593 https://issues.apache.org/jira/browse/CALCITE-2764
Multi-sorted table are rare in pratice, mutil-distributed table doesn't exist either. Values node with several tuples is not worth optimization, with many tuples is not worth optimization either, because the time it takes optimizer to figure out the ordering may be longer than just sort it in runtime. In issue https://issues.apache.org/jira/browse/CALCITE-1990, Leo extended RelDistribution to inherit RelMultipleTrait, just like RelCollation does, to solve his problem in the example. But I don't think this is an appropriate way to represent the equivalence classes (in PostgreSQL's term). So why did we introduce RelCompisteTrait and RelMultipleTrait in the beginning? Seems like it gives us more pain than gain. Thanks ~ Haisheng Yuan
