+ Building the materialized view function for schema_change here based on defineExpr.
+ This is a trick because the current storage layer does not support expression evaluation.
+ count distinct materialized view will set mv_expr with to_bitmap or hll_hash.
+ count materialized view will set mv_expr with count.
+ Support to regenerate historical data when a new materialized view is created in BE。
+ Support to_bitmap function
+ Support hll_hash function
+ Support count(field) function
For #3344
5032b7fe7a