[ https://issues.apache.org/jira/browse/SPARK-12049?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Marcelo Vanzin resolved SPARK-12049. ------------------------------------ Resolution: Fixed Fix Version/s: 1.6.0 1.5.3 > User JVM shutdown hook can cause deadlock at shutdown > ----------------------------------------------------- > > Key: SPARK-12049 > URL: https://issues.apache.org/jira/browse/SPARK-12049 > Project: Spark > Issue Type: Bug > Components: Spark Core > Affects Versions: 1.5.2, 1.6.0 > Reporter: Sean Owen > Assignee: Sean Owen > Fix For: 1.5.3, 1.6.0 > > > Here's a simplification of a deadlock that can occur a shutdown if the user > app has also installed a shutdown hook to clean up: > - Spark Shutdown Hook thread runs > - {{SparkShutdownHookManager.runAll()}} is invoked, locking > {{SparkShutdownHookManager}} as it is {{synchronized}} > - A user shutdown hook thread runs > - User hook tries to call, for example {{StreamingContext.stop()}}, which is > {{synchronized}} and locks it > - User hook blocks when the {{StreamingContext}} tries to {{remove()}} the > Spark Streaming shutdown task, since it's {{synchronized}} per above > - Spark Shutdown Hook tries to execute the Spark Streaming shutdown task, but > blocks on {{StreamingContext.stop()}} > I think this is actually not that critical, since it requires a pretty > specific setup, and I think it can be worked around in many cases by > integrating with Hadoop's shutdown hook mechanism like Spark does so that > these happen serially. > I also think it's solvable in the code by not locking > {{SparkShutdownHookManager}} in the 3 methods that are {{synchronized}} since > these are really only protecting {{hooks}}. {{runAll()}} shouldn't hold the > lock while executing hooks. -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org