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https://issues.apache.org/jira/browse/HIVE-24363?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Pravin Sinha reassigned HIVE-24363:
-----------------------------------
> Current order of transactional event listeners is prone to deadlock in
> backend DB connections
> ---------------------------------------------------------------------------------------------
>
> Key: HIVE-24363
> URL: https://issues.apache.org/jira/browse/HIVE-24363
> Project: Hive
> Issue Type: Bug
> Reporter: Pravin Sinha
> Assignee: Pravin Sinha
> Priority: Major
>
> Currently the AcidEventListener is added to the end of list transactional
> event listeners. When DbNotificationListener is configured in
> 'hive.metastore.transactional.event.listeners'. The list will be formed as :
> {"DbNotificationListener" , "AcidEventListener"}
> This will result in backend DB lock acquisition in this order:
> {code:java}
> lock(a) {
> // perform some op on a
> lock(b) {
> // perform some op on b
> }
> }
> {code}
> On the other hand, there are some HMS API say for example commit_txn(), which
> calls the TxnHandler method directly, followed by DbNotificationListener
> processing. Which will result in the lock acquisition in reverse order:
> {code:java}
> lock(b) {
> // perform some op on b
> lock(a) {
> // perform some op on a
> }
> }
> {code}
> Note: 'a' and 'b' above are backend DB lock and not a jvm lock.
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