Pravin Sinha created HIVE-24363:
-----------------------------------
Summary: 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
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.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
