Details
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Bug
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Status: Resolved
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Major
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Resolution: Duplicate
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0.12.0
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None
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None
Description
When parsing/analyzing query, hive treats partition predicate value as int instead of string. This breaks down and leads to incorrect result when the partition predicate value starts with int 0, e.g: hour=00, hour=05 etc.
The following repro illustrates the bug:
– create test table and partition, populate with some data
create table test_partition_pred(col1 int) partitioned by (hour STRING);
insert into table test_partition_pred partition (hour=00) select 21 FROM some_table limit 1;
– this query returns incorrect results, i.e. just empty set.
select * from test_partition_pred where hour=00;
OK
– this query returns correct result. Note predicate value is string literal
select * from test_partition_pred where hour='00';
OK
21 00
explain plan illustrates how the query was interpreted. Particularly the partition predicate is pushed down as regular filter clause, with hour=0 as predicate. See attached explain plan file.
Note:
1. The type of the partition column is defined as string, not int.
2. This is a regression in Hive 0.12. This used to work in Hive 0.11
3. Not an issue when the partition value starts with integer other than 0, e.g hour=10, hour=11 etc.
4. As seen above, workaround is to use string literal hour='00' etc.
This should not be too bad if in the failing case hive complains that partition hour=0 is not found, or complains literal type doesn't match column type. Instead hive silently pushes it down as filter clause, and query succeeds with empty set as result.
We found this out in our production tables partitioned by hour, only a few days after it started occurring, when there were empty data sets for partitions hour=00 to hour=09.
Attachments
Attachments
Issue Links
- Is contained by
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HIVE-4914 filtering via partition name should be done inside metastore server (implementation)
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- Resolved
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