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https://issues.apache.org/jira/browse/HIVE-3149?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kevin Wilfong updated HIVE-3149:
--------------------------------
Description:
When creating partitions in a table using dynamic partitions and a Block level
merge is executed at the end of the query, some partitions may be lost.
Specifically if the values of two or more dynamic partition keys end in the
same sequence of numbers, all but the largest will be dropped.
I was not able to confirm it, but I suspect that if a map reduce job is
speculated as part of the merge, the duplicate data will not be deleted either.
E.g.
insert overwrite table merge_dynamic_part partition (ds = '2008-04-08', hr)
select key, value, if(key % 2 == 0, 'a1', 'b1') as hr from srcpart_merge_dp_rc
where ds = '2008-04-08';
In this query, if a Block level merge is executed at the end, only one of the
partitions ds=2008-04-08/hr=a1 and ds=2008-04-08/hr=b1 will appear in the final
table.
was:
When creating partitions in a table using dynamic partitions and a Block Merge
Task is executed at the end of the query, some partitions may be lost.
Specifically if the values of two or more dynamic partition keys end in the
same sequence of numbers, all but the largest will be dropped.
I was not able to confirm it, but I suspect that if a map reduce job is
speculated as part of the merge, the duplicate data will not be deleted either.
E.g.
insert overwrite table merge_dynamic_part partition (ds = '2008-04-08', hr)
select key, value, if(key % 2 == 0, 'a1', 'b1') as hr from srcpart_merge_dp_rc
where ds = '2008-04-08';
In this query, if a Block Merge Task is executed at the end, only one of the
partitions ds=2008-04-08/hr=a1 and ds=2008-04-08/hr=b1 will appear in the final
table.
Summary: Dynamically generated paritions deleted by Block level merge
(was: Dynamically generated paritions deleted by BlockMergeTask)
> Dynamically generated paritions deleted by Block level merge
> ------------------------------------------------------------
>
> Key: HIVE-3149
> URL: https://issues.apache.org/jira/browse/HIVE-3149
> Project: Hive
> Issue Type: Bug
> Components: Query Processor
> Reporter: Kevin Wilfong
> Assignee: Kevin Wilfong
> Priority: Critical
> Fix For: 0.10.0
>
>
> When creating partitions in a table using dynamic partitions and a Block
> level merge is executed at the end of the query, some partitions may be lost.
> Specifically if the values of two or more dynamic partition keys end in the
> same sequence of numbers, all but the largest will be dropped.
> I was not able to confirm it, but I suspect that if a map reduce job is
> speculated as part of the merge, the duplicate data will not be deleted
> either.
> E.g.
> insert overwrite table merge_dynamic_part partition (ds = '2008-04-08', hr)
> select key, value, if(key % 2 == 0, 'a1', 'b1') as hr from
> srcpart_merge_dp_rc where ds = '2008-04-08';
> In this query, if a Block level merge is executed at the end, only one of the
> partitions ds=2008-04-08/hr=a1 and ds=2008-04-08/hr=b1 will appear in the
> final table.
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