[DRILL-5394] Optimize query planning for MapR-DB tables by caching row counts

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.9.0, 1.10.0
• Fix Version/s: 1.11.0
• Component/s: Query Planning & Optimization, Storage - MapRDB
• Labels: MapR-DB-Binary ready-to-commit
• Assignee: Padma Penumarthy
• Reporter: Abhishek Girish
• Reviewer: Gautam Parai
• Created: 29/Mar/17 01:06
• Updated: 14/May/17 00:45
• Resolved: 03/Apr/17 05:14

Description

On large MapR-DB tables, it was observed that the query planning time was longer than expected. With DEBUG logs, it was understood that there were multiple calls being made to get MapR-DB region locations and to fetch total row count for tables.

2017-02-23 13:59:55,246 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.s.m.d.b.BinaryTableGroupScan - Getting region locations
2017-02-23 14:00:05,006 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.planner.logical.DrillOptiq - Function
...
2017-02-23 14:00:05,031 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.s.m.d.b.BinaryTableGroupScan - Getting region locations
2017-02-23 14:00:16,438 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.planner.logical.DrillOptiq - Special
...
2017-02-23 14:00:16,439 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.s.m.d.b.BinaryTableGroupScan - Getting region locations
2017-02-23 14:00:28,479 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.planner.logical.DrillOptiq - Special
...
2017-02-23 14:00:28,480 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.s.m.d.b.BinaryTableGroupScan - Getting region locations
2017-02-23 14:00:42,396 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.planner.logical.DrillOptiq - Special
...
2017-02-23 14:00:42,397 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.s.m.d.b.BinaryTableGroupScan - Getting region locations
2017-02-23 14:00:54,609 [27513143-8718-7a47-a2d4-06850755568a:foreman] DEBUG o.a.d.e.p.s.h.DefaultSqlHandler - VOLCANO:Physical Planning (49588ms):

We should cache these stats and reuse them where all required during query planning. This should help reduce query planning time.

Issue Links

• links to: GitHub Pull Request #802