[jira] [Created] (DRILL-3419) Ambiguity in query plan when we do partition pruning

["Khurram Faraaz (JIRA)" <ji...@apache.org>]

Khurram Faraaz created DRILL-3419:
-------------------------------------

             Summary: Ambiguity in query plan when we do partition pruning
                 Key: DRILL-3419
                 URL: https://issues.apache.org/jira/browse/DRILL-3419
             Project: Apache Drill
          Issue Type: Bug
          Components: Query Planning & Optimization
    Affects Versions: 1.1.0
            Reporter: Khurram Faraaz
            Assignee: Jinfeng Ni


Note that in case (1) and case (2) we prune, however it is not clear if we prune is case (3), that is because we see a FILTER in the query plan in case (3)

CTAS 
{code}
0: jdbc:drill:schema=dfs.tmp> CREATE TABLE CTAS_ONE_MILN_RWS_PER_GROUP(col1, col2) PARTITION BY (col2) AS select cast(columns[0] as bigint) col1, cast(columns[1] as char(2)) col2 from `millionValGroup.csv`;
+-----------+----------------------------+
| Fragment  | Number of records written  |
+-----------+----------------------------+
| 1_1       | 21932064                   |
| 1_0       | 28067936                   |
+-----------+----------------------------+
2 rows selected (73.661 seconds)
{code}

case 1)

{code}
explain plan for select col1, col2 from CTAS_ONE_MILN_RWS_PER_GROUP where col2 LIKE '%Z%';

| 00-00    Screen
00-01      Project(col1=[$0], col2=[$1])
00-02        UnionExchange
01-01          Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP/1_0_3.parquet], ReadEntryWithPath [path=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP/1_1_3.parquet]], selectionRoot=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP, numFiles=2, columns=[`col2`, `col1`]]])
{code}

case 2)

{code}
explain plan for select col1, col2 from CTAS_ONE_MILN_RWS_PER_GROUP where col2 LIKE 'A%';

| 00-00    Screen
00-01      Project(col1=[$0], col2=[$1])
00-02        UnionExchange
01-01          Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP/1_0_3.parquet], ReadEntryWithPath [path=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP/1_0_2.parquet], ReadEntryWithPath [path=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP/1_1_1.parquet], ReadEntryWithPath [path=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP/1_1_2.parquet], ReadEntryWithPath [path=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP/1_1_3.parquet], ReadEntryWithPath [path=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP/1_0_1.parquet]], selectionRoot=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP, numFiles=6, columns=[`col2`, `col1`]]])
{code}

case 3) we are NOT pruning here.

{code}
explain plan for select col1, col2 from CTAS_ONE_MILN_RWS_PER_GROUP where col2 LIKE 'Z%';

| 00-00    Screen
00-01      Project(col1=[$1], col2=[$0])
00-02        SelectionVectorRemover
00-03          Filter(condition=[LIKE($0, 'Z%')])
00-04            Project(col2=[$1], col1=[$0])
00-05              Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP/1_1_48.parquet]], selectionRoot=/tmp/CTAS_ONE_MILN_RWS_PER_GROUP, numFiles=1, columns=[`col2`, `col1`]]])
{code}



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