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https://issues.apache.org/jira/browse/HIVE-19490?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16471031#comment-16471031
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Eugene Koifman commented on HIVE-19490:
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TestDbTxnManager2 has many tests to verify locks
I think using shared lock for Druid insert makes sense but I'm not sure if that
is appropriate for all non-native tables.
> Locking on Insert into for non native and managed tables.
> ---------------------------------------------------------
>
> Key: HIVE-19490
> URL: https://issues.apache.org/jira/browse/HIVE-19490
> Project: Hive
> Issue Type: Improvement
> Components: Druid integration
> Reporter: slim bouguerra
> Assignee: slim bouguerra
> Priority: Major
> Labels: druid, locking
> Attachments: HIVE-19490.patch
>
>
> Current state of the art:
> Managed non native table like Druid Tables, will need to get a Lock on Insert
> into or insert Over write. The nature of this lock is set to Exclusive by
> default for any non native table.
> This implies that Inserts into Druid table will Lock any read query as well
> during the execution of the insert into. IMO this lock (on insert into) is
> not needed since the insert statement is appending data and the state of
> loading it is managed partially by Hive Storage handler hook and part of it
> by Druid.
> What i am proposing is to relax the lock level to shared for all non native
> tables on insert into operations and keep it as Exclusive Write for insert
> Overwrite for now.
>
> Any feedback is welcome.
> cc [~ekoifman] / [~ashutoshc] / [~jdere] / [~hagleitn]
> Also am not sure what is the best way to unit test this currently am using
> debugger to check of locks are what i except, please let me know if there is
> a better way to do this.
>
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