[HIVE-20366] TPC-DS query78 stats estimates are off for is null filter - ASF JIRA

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Details

Type: Bug
Status: Closed
Priority: Major
Resolution: Fixed
Affects Version/s: None
Fix Version/s: 4.0.0-alpha-1
Component/s: Query Planning
Labels:
None

Target Version/s:

4.0.0

Description

In Query 78, there is Left outer join between fact table combos: stores_sales LOJ store_returns, catalog_sales LOJ catalog_returns and web_sales LOJ web_returns. Each of these joins estimates only a single row and the result is BROADCAST and causes hash table memory errors

         Reducer 12                                 |
|             Execution mode: vectorized, llap       |
|             Reduce Operator Tree:                  |
+----------------------------------------------------+
|                      Explain                       |
+----------------------------------------------------+
|               Map Join Operator                    |
|                 condition map:                     |
|                      Left Outer Join 0 to 1        |
|                 keys:                              |
|                   0 KEY.reducesinkkey0 (type: bigint), KEY.reducesinkkey1 (type: bigint) |
|                   1 KEY.reducesinkkey0 (type: bigint), KEY.reducesinkkey1 (type: bigint) |
|                 outputColumnNames: _col0, _col1, _col3, _col4, _col5, _col6, _col8 |
|                 input vertices:                    |
|                   1 Map 14                         |
|                 Statistics: Num rows: 10282477384 Data size: 534184867432 Basic stats: COMPLETE Column stats: COMPLETE |
|                 Filter Operator                    |
|                   predicate: _col8 is null (type: boolean) |
|                  * Statistics: Num rows: 1* Data size: 52 Basic stats: COMPLETE Column stats: COMPLETE |