Performing Manual Compactions
Hive administrators use the ALTER TABLE DDL command to queue
requests that compact base and delta files for a table or partition:
ALTER TABLE tablename [PARTITION (partition_key='partition_value' [,...])] COMPACT 'compaction_type'
Use the SHOW COMPACTIONS command to monitor the progress of the
compactions:
SHOW COMPACTIONS
![[Note]](../common/images/admon/note.png) | Note |
|---|---|
ALTER TABLE will compact tables even if the NO_AUTO_COMPACTION table property is set. |
The SHOW COMPACTIONS command provides the following output for
each compaction:
Database name
Table name
Partition name
Major or minor compaction
Compaction state:
Initiated - waiting in queue
Working - currently compacting
Ready for cleaning - compaction completed and old files scheduled for removal
Thread ID
Start time of compaction
Hive administrators can also view a list of currently open and aborted transactions
with the the SHOW TRANSACTIONS command. This command provides the
following output for each transaction:
Transaction ID
Transaction state
Hive user who initiated the transaction
Host machine where transaction was initiated