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https://issues.apache.org/jira/browse/DRILL-4676?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15285368#comment-15285368
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ASF GitHub Bot commented on DRILL-4676:
---------------------------------------
Github user adeneche commented on a diff in the pull request:
https://github.com/apache/drill/pull/503#discussion_r63430234
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/work/foreman/Foreman.java ---
@@ -1221,6 +1223,12 @@ public void interrupted(final InterruptedException
e) {
* to the user
*/
public void moveToState(final QueryState newState, final Exception ex)
{
+ // if the current thread is the foreman thread, throw an exception
+ // otherwise the foreman will be blocked forever on
acceptExternalEvents
+ if (myThreadRef == Thread.currentThread()) {
--- End diff --
This won't work when submitting remote fragments as the moveToState method
can be called either by the foreman thread or by an rpc thread.
Anyway, I'm working on a better fix that would remove the latch completely.
> Foreman.moveToState can block forever if called by the foreman thread while
> the query is still being setup
> ----------------------------------------------------------------------------------------------------------
>
> Key: DRILL-4676
> URL: https://issues.apache.org/jira/browse/DRILL-4676
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Flow
> Affects Versions: 1.6.0
> Reporter: Deneche A. Hakim
> Assignee: Sudheesh Katkam
> Fix For: 1.7.0
>
>
> When the query is being setup, foreman has a special CountDownLatch that
> blocks rpc threads from delivering external events, this latch is unblocked
> at the end of the query setup.
> In some cases though, when the foreman is submitting remote fragments, a
> failure in RpcBus.send() causes an exception to be thrown that is reported to
> Foreman.FragmentSubmitListener and blocks in the CountDownLatch. This causes
> the foreman thread to block forever, and can rpc threads to be blocked too.
> This seems to happen more frequently at a high concurrency load, and also can
> prevent clients from connecting to the Drillbits.
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