Vihang Karajgaonkar created HIVE-15880:
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Summary: Allow insert overwrite query to use auto.purge table
property
Key: HIVE-15880
URL: https://issues.apache.org/jira/browse/HIVE-15880
Project: Hive
Issue Type: Improvement
Reporter: Vihang Karajgaonkar
Assignee: Vihang Karajgaonkar
It seems inconsistent that auto.purge property is not considered when we do a
INSERT OVERWRITE while it is when we do a DROP TABLE
Drop table doesn't move table data to Trash when auto.purge is set to true
{noformat}
> create table temp(col1 string, col2 string);
No rows affected (0.064 seconds)
> alter table temp set tblproperties('auto.purge'='true');
No rows affected (0.083 seconds)
> insert into temp values ('test', 'test'), ('test2', 'test2');
No rows affected (25.473 seconds)
# hdfs dfs -ls /user/hive/warehouse/temp
Found 1 items
-rwxrwxrwt 3 hive hive 22 2017-02-09 13:03
/user/hive/warehouse/temp/000000_0
#
> drop table temp;
No rows affected (0.242 seconds)
# hdfs dfs -ls /user/hive/warehouse/temp
ls: `/user/hive/warehouse/temp': No such file or directory
#
# sudo -u hive hdfs dfs -ls /user/hive/.Trash/Current/user/hive/warehouse
#
{noformat}
INSERT OVERWRITE query moves the table data to Trash even when auto.purge is
set to true
{noformat}
> create table temp(col1 string, col2 string);
> alter table temp set tblproperties('auto.purge'='true');
> insert into temp values ('test', 'test'), ('test2', 'test2');
# hdfs dfs -ls /user/hive/warehouse/temp
Found 1 items
-rwxrwxrwt 3 hive hive 22 2017-02-09 13:07
/user/hive/warehouse/temp/000000_0
#
> insert overwrite table temp select * from dummy;
# hdfs dfs -ls /user/hive/warehouse/temp
Found 1 items
-rwxrwxrwt 3 hive hive 26 2017-02-09 13:08
/user/hive/warehouse/temp/000000_0
# sudo -u hive hdfs dfs -ls /user/hive/.Trash/Current/user/hive/warehouse
Found 1 items
drwx------ - hive hive 0 2017-02-09 13:08
/user/hive/.Trash/Current/user/hive/warehouse/temp
#
{noformat}
While move operations are not very costly on HDFS it could be significant
overhead on slow FileSystems like S3. This could improve the performance of
{{INSERT OVERWRITE TABLE}} queries especially when there are large number of
partitions on tables located on S3 should the user wish to set auto.purge
property to true
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