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https://issues.apache.org/jira/browse/HIVE-11388?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15066872#comment-15066872
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Eugene Koifman commented on HIVE-11388:
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I agree that the "hostname" field may is useful.
The idea is that Initiator thread is running in each metastore.
But if it needs to perform some operation in a way that another Initiator
doesn't attempt the same, then the row in MUTEX_TABLE with key="initiator" will
be locked using Select for Update to provide exclusive access. If it dies, DB
will automatically release the lock and another Initiator instance will be able
to proceed.
> there should only be 1 Initiator for compactions per Hive installation
> ----------------------------------------------------------------------
>
> Key: HIVE-11388
> URL: https://issues.apache.org/jira/browse/HIVE-11388
> Project: Hive
> Issue Type: Bug
> Components: Transactions
> Affects Versions: 1.0.0
> Reporter: Eugene Koifman
> Assignee: Eugene Koifman
> Priority: Critical
>
> org.apache.hadoop.hive.ql.txn.compactor.Initiator is a thread that runs
> inside the metastore service to manage compactions of ACID tables. There
> should be exactly 1 instance of this thread (even with multiple Thrift
> services).
> This is documented in
> https://cwiki.apache.org/confluence/display/Hive/Hive+Transactions#HiveTransactions-Configuration
> but not enforced.
> Should add enforcement, since more than 1 Initiator could cause concurrent
> attempts to compact the same table/partition - which will not work.
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