[jira] [Assigned] (HIVE-23236) Remove the global lock from acquireLock

["Marton Bod (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-23236?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Marton Bod reassigned HIVE-23236:
---------------------------------


> Remove the global lock from acquireLock
> ---------------------------------------
>
>                 Key: HIVE-23236
>                 URL: https://issues.apache.org/jira/browse/HIVE-23236
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Marton Bod
>            Assignee: Marton Bod
>            Priority: Major
>
> Currently we have a global lock (NEXT_LOCK_ID) when running enqueueLock, because the algorithm in checkLock requires the locks to have a well defined order, and also requires that every lock component is already stored in the RDBMS before checking the locks.
> Proposed approach:
>  * Enqueue lock without a global lock, using a sequence for getting the next lock ID
>  * Insert the locks as usual, but with an additional timestamp (enqueued_at)
>  * Check lock should check all enqueued locks for the given db/table/partition but order should be determined based on the enqueued_at time instead of the lockID
>  * If there is no blocking lock, update the state to acquired as usual



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