we save bi-map in cte consumer to get the maping between producer and consumer. the consumer's output is decided by the map in it. so, cte consumer should be output prunable, and should remove useless entry from map when do column pruning
we save bi-map in cte consumer to get the maping between producer and consumer. the consumer's output is decided by the map in it. so, cte consumer should be output prunable, and should remove useless entry from map when do column pruning