When there is count(*) function in query, we only need to scan the smallest column. For example: Query: select count(*) from (select k1, k2, k3 from base) tmp; Only k1 which is the smallest column should be scanned. The remaining columns (k2, k3) should be pruning. This pr achieves this optimization of column pruning. Fixed #5409
# fe-common This module is used to store some common classes of other modules. # spark-dpp This module is Spark DPP program, used for Spark Load function. Depends: fe-common # fe-core This module is the main process module of FE. Depends: fe-common, spark-dpp