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

["Abhishek Girish (JIRA)" <ji...@apache.org>]

Abhishek Girish created DRILL-5394:
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             Summary: Optimize query planning for MapR-DB tables by caching row counts
                 Key: DRILL-5394
                 URL: https://issues.apache.org/jira/browse/DRILL-5394
             Project: Apache Drill
          Issue Type: Improvement
          Components: Query Planning & Optimization, Storage - MapRDB
    Affects Versions: 1.9.0, 1.10.0
            Reporter: Abhishek Girish
            Assignee: Padma Penumarthy
             Fix For: 1.11.0


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.

{code}
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):
{code}

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





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