[HIVE-18215] Possible code optimization exists for "INSERT OVERWITE on MM table. SELECT FROM (SELECT .. UNION ALL SELECT ..)

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 3.0.0
• Component/s: HiveServer2
• Assignee: Steve Yeom
• Reporter: Steve Yeom
• Created: 04/Dec/17 22:21
• Updated: 21/Oct/22 07:20

Description

removeTempOrDuplicateFiles(.) has an opportunity for performance code optimization for the
test case of "INSERT OVERWITE on MM table. SELECT FROM (SELECT .. UNION ALL SELECT ..)" from dp_counter_mm.q.

This is MM table specific and we can avoid calling fs.exists() by creating a specific mmDirectories
list for the current SELECT statement (out of two SELECTs in our test case from
the dp_counter_mm.q) from the IOW union all query.