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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