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https://issues.apache.org/jira/browse/HIVE-13966?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15346431#comment-15346431
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Reuben Kuhnert commented on HIVE-13966:
---------------------------------------
Seems like it might make sense to use an interface like
{{TransactionalMetastoreEventListener}} or something so that we can enforce
compile time safety. Then just tag the relevant classes with said interface so
that we can have loops of type (with compile time check):
{code}
for (TransactionalMetaStoreEventListener listener : listeners) { ... }
{code}
This allows alows you to enforce that listeners dropped into the
{{<name>hive.metastore.synchronous.event.listeners</name>}} bucket all expect
to be called within a transaction.
Alternatively, it might make sense to invert control such that listeners that
care about transactional updates can listen for them, while leaving others
unaffected:
{code}
class MetastoreEventListener {
public abstract onTransactionalEvent(SomeEvent event); // Transactionals will
listen for this
public abstract onEvent(SomeEvent event); // Everyone else will listen for
this.
}
{code}
Transactional listeners will implement the first while leaving the second as a
{{noop}}.
$0.02
> DbNotificationListener: can loose DDL operation notifications
> -------------------------------------------------------------
>
> Key: HIVE-13966
> URL: https://issues.apache.org/jira/browse/HIVE-13966
> Project: Hive
> Issue Type: Bug
> Components: HCatalog
> Reporter: Nachiket Vaidya
> Assignee: Rahul Sharma
> Priority: Critical
>
> The code for each API in HiveMetaStore.java is like this:
> 1. openTransaction()
> 2. -- operation--
> 3. commit() or rollback() based on result of the operation.
> 4. add entry to notification log (unconditionally)
> If the operation is failed (in step 2), we still add entry to notification
> log. Found this issue in testing.
> It is still ok as this is the case of false positive.
> If the operation is successful and adding to notification log failed, the
> user will get an MetaException. It will not rollback the operation, as it is
> already committed. We need to handle this case so that we will not have false
> negatives.
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