Rahul Challapalli created DRILL-3418:
----------------------------------------
Summary: Partition Pruning : We are over-pruning and this leads to
wrong results
Key: DRILL-3418
URL: https://issues.apache.org/jira/browse/DRILL-3418
Project: Apache Drill
Issue Type: Bug
Components: Query Planning & Optimization
Reporter: Rahul Challapalli
Assignee: Steven Phillips
Priority: Critical
Fix For: 1.1.0
git.commit.id.abbrev=c199860
We are over-pruning based on the below plan.
{code}
explain plan for select * from
`existing_partition_pruning/lineitem_hierarchical_intstring` where (dir0=1993
or dir1='jun') and (dir0=1991 or dir1='aug' or columns[0] > 5000);
00-00 Screen
00-01 Project(*=[$0])
00-02 Project(T17¦¦*=[$0])
00-03 SelectionVectorRemover
00-04 Filter(condition=[AND(OR(=($1, 1993), =($2, 'jun')), OR(=($1,
1991), =($2, 'aug'), >(ITEM($3, 0), 5000)))])
00-05 Project(T17¦¦*=[$0], dir0=[$1], dir1=[$2], columns=[$3])
00-06 Scan(groupscan=[ParquetGroupScan
[entries=[ReadEntryWithPath
[path=/drill/testdata/ctas_auto_partition/existing_partition_pruning/lineitem_hierarchical_intstring/0_0_26.parquet],
ReadEntryWithPath
[path=/drill/testdata/ctas_auto_partition/existing_partition_pruning/lineitem_hierarchical_intstring/0_0_7.parquet]],
selectionRoot=/drill/testdata/ctas_auto_partition/existing_partition_pruning/lineitem_hierarchical_intstring,
numFiles=2, columns=[`*`]]])
{code}
We have 7 year partitions and each year has 12 further month partitions.
I executed a count(*) query based on the above filters with & without
partitioning in place and the values were different
Without Partitions :
{code}
select count(*) from tbl_nopartitions where (dir0=1993 or dir1='jun') and
(dir0=1991 or dir1='aug' or columns[0] > 5000);
+---------+
| EXPR$0 |
+---------+
| 14515 |
+---------+
1 row selected (0.903 seconds)
{code}
With Partitions :
{code}
select count(*) from
`existing_partition_pruning/lineitem_hierarchical_intstring` where (dir0=1993
or dir1='jun') and (dir0=1991 or dir1='aug' or columns[0] > 5000);
+---------+
| EXPR$0 |
+---------+
| 1800 |
+---------+
1 row selected (0.49 seconds)
{code}
The data is larger than 10 MB to upload here
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