[ https://issues.apache.org/jira/browse/CASSANDRA-14554?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Benedict updated CASSANDRA-14554: --------------------------------- Summary: Streaming needs to synchronise access to LifecycleTransaction (was: LifecycleTransaction encounters ConcurrentModificationException when used in multi-threaded context) > Streaming needs to synchronise access to LifecycleTransaction > ------------------------------------------------------------- > > Key: CASSANDRA-14554 > URL: https://issues.apache.org/jira/browse/CASSANDRA-14554 > Project: Cassandra > Issue Type: Bug > Components: Streaming and Messaging > Reporter: Dinesh Joshi > Assignee: Stefania > Priority: Major > Fix For: 4.0, 3.0.x, 3.11.x > > > When LifecycleTransaction is used in a multi-threaded context, we encounter > this exception - > {quote}java.util.ConcurrentModificationException: null > at > java.util.LinkedHashMap$LinkedHashIterator.nextNode(LinkedHashMap.java:719) > at java.util.LinkedHashMap$LinkedKeyIterator.next(LinkedHashMap.java:742) > at java.lang.Iterable.forEach(Iterable.java:74) > at > org.apache.cassandra.db.lifecycle.LogReplicaSet.maybeCreateReplica(LogReplicaSet.java:78) > at org.apache.cassandra.db.lifecycle.LogFile.makeRecord(LogFile.java:320) > at org.apache.cassandra.db.lifecycle.LogFile.add(LogFile.java:285) > at > org.apache.cassandra.db.lifecycle.LogTransaction.trackNew(LogTransaction.java:136) > at > org.apache.cassandra.db.lifecycle.LifecycleTransaction.trackNew(LifecycleTransaction.java:529) > {quote} > During streaming we create a reference to a {{LifeCycleTransaction}} and > share it between threads - > [https://github.com/apache/cassandra/blob/5cc68a87359dd02412bdb70a52dfcd718d44a5ba/src/java/org/apache/cassandra/db/streaming/CassandraStreamReader.java#L156] > This is used in a multi-threaded context insideĀ {{CassandraIncomingFile}} > which is anĀ {{IncomingStreamMessage}}. This is being deserialized in parallel. > {{LifecycleTransaction}} is not meant to be used in a multi-threaded context > and this leads to streaming failures due to object sharing. On trunk, this > object is shared across all threads that transfer sstables in parallel for > the given {{TableId}} in a {{StreamSession}}. There are two options to solve > this - make {{LifecycleTransaction}} and the associated objects thread safe, > scope the transaction to a single {{CassandraIncomingFile}}. The consequences > of the latter option is that if we experience streaming failure we may have > redundant SSTables on disk. This is ok as compaction should clean this up. A > third option is we synchronize access in the streaming infrastructure. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org