mirror of
https://github.com/apache/impala.git
synced 2025-12-30 21:02:41 -05:00
57d7c614bc
Instead of materializing empty rows when computing count star, we use the data stored in the Parquet RowGroup.num_rows field. The Parquet scanner tuple is modified to have one slot into which we will write the num rows statistic. The aggregate function is changed from count to a special sum function that gets initialized to 0. We also add a rewrite rule so that count(<literal>) is rewritten to count(*) in order to make sure that this optimization is applied in all cases. Testing: - Added functional and planner tests Change-Id: I536b85c014821296aed68a0c68faadae96005e62 Reviewed-on: http://gerrit.cloudera.org:8080/6812 Reviewed-by: Taras Bobrovytsky <tbobrovytsky@cloudera.com> Tested-by: Impala Public Jenkins