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https://issues.apache.org/jira/browse/HIVE-24336?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Work on HIVE-24336 started by Marta Kuczora.
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> Turn off the direct insert for EXPLAIN ANALYZE queries
> ------------------------------------------------------
>
> Key: HIVE-24336
> URL: https://issues.apache.org/jira/browse/HIVE-24336
> Project: Hive
> Issue Type: Bug
> Reporter: Marta Kuczora
> Assignee: Marta Kuczora
> Priority: Major
> Labels: pull-request-available
> Fix For: 4.0.0
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> If we do an EXPLAIN ANALYZE for an INSERT query with direct insert on, the
> new files will be created in the table directory, and they won't be
> cleaned-up when the EXPLAIN query is finished.
> Example:
> {noformat}
> create table analyze_table (id int) stored as orc
> tblproperties('transactional'='true');
> explain analyze insert into analyze_table values (1),(2),(3),(4);
> select * from analyze_table;
> 1
> 2
> 3
> 4
> Time taken: 0.1 seconds, Fetched: 4 row(s)
> The result should be empty after the explain command.
> {noformat}
> An EXPLAIN ANALYZE query will execute the actual query and the files will be
> created within the staging directory, but the MoveTask won't move them to the
> final location. So when the EXPLAIN ANALYZE query is finished, the staging
> directory will be deleted, and the table directory will be the same as before
> the EXPLAIN query. But with direct insert on the files will be written into
> the table directory, so an additional cleanup would be necessary in order to
> restore the files within the table directory to the state before the EXPLAIN
> ANALYZE query. This could be avoided by turning off the direct insert for an
> EXPLAIN ANALYZE query. Since the direct insert improves the performance by
> eliminating the file movements within the MoveTask, but it has no affect on
> the query execution plan it can be safely turned off for explain queries.
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