Integrate MaterializedViewRule into Apache Kylin

I am trying to integrate MaterializedViewRule into Apache Kylin. We need an index structure to find matched indexes since there are ten thousand materializations. The current MaterializedViewRule class hierarchy has 3 different duties: 1. Pattern match: e.g. xxOnlyAggregateRule, xxOnlyJoinRule

Support Left out join in RelMdExpressionLineage

Hi jesusca I am investigating how to extend MaterializedViewRule to support left outer join. The first issue which I met is supporting outer join in RelMdExpressionLineage#getExpressionLineage() I think the current implementation also fits in the outer join case, and to support outer join only ne