[
https://issues.apache.org/jira/browse/CASSANDRA-14554?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16691225#comment-16691225
]
Stefania edited comment on CASSANDRA-14554 at 11/19/18 4:00 AM:
----------------------------------------------------------------
For trunk, we should probably either introduce a synchronized transaction and
add references in the writers, or look into child transactions.
The patch I proposed is suitable for released branches. I see this ticket is
now classified for 4.0 only. In my opinion, there is an issue also for 3.0 and
3.11. The explanation is in my original
[comment|https://issues.apache.org/jira/browse/CASSANDRA-14554?focusedCommentId=16677739&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16677739].
Perhaps we should create a different ticket for this problem and commit the
patch only to 3.0 and 3.11?
I also would like to follow up with a more comprehensive approach for trunk but
I don't know when I'll have time to work on this. I'll post another update if I
do start work.
was (Author: stefania):
For trunk we should probably either introduce a synchronized transaction and
add references in the writers, or look into child transactions.
The patch I proposed is suitable for released branches however. I see this
ticket is now classified for 4.0 only. In my opinion there is an issue also for
3.0 and 3.11.The explanation is in my original comment. Perhaps we should
create a different ticket for this problem and commit the patch only to 3.0 and
3.11?
I also would like to follow up with a more comprehensive approach for trunk but
I don't know when I'll have time to work on this. I'll post another update if I
do start work however.
> LifecycleTransaction encounters ConcurrentModificationException when used in
> multi-threaded context
> ---------------------------------------------------------------------------------------------------
>
> 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: Dinesh Joshi
> Priority: Major
> Fix For: 4.0
>
>
> 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 inside {{CassandraIncomingFile}}
> which is an {{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
