[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15991146#comment-15991146
]
Ariel Weisberg commented on CASSANDRA-13265:
--------------------------------------------
So the dtests failing on the branch don't match the failures on trunk, but I
looked at some of the other branches and they are also failing similar random
tests. So I am running trunk using the branch job to see what the test failures
look like in that scenario. I don't think you broke anything it's just doing
due diligence is a pain right now.
I looked at the utests and they look fine. Right now it runs 4 containers, but
the first container is most important as that is where the tests are closest to
zero failures since we only used to run those on every commit. The others
failures don't look related (famous last words).
Meanwhile can you squash the branches that aren't squashed?
> Expiration in OutboundTcpConnection can block the reader Thread
> ---------------------------------------------------------------
>
> Key: CASSANDRA-13265
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13265
> Project: Cassandra
> Issue Type: Bug
> Environment: Cassandra 3.0.9
> Java HotSpot(TM) 64-Bit Server VM version 25.112-b15 (Java version
> 1.8.0_112-b15)
> Linux 3.16
> Reporter: Christian Esken
> Assignee: Christian Esken
> Fix For: 3.0.x
>
> Attachments: cassandra-13265-2.2-dtest_stdout.txt,
> cassandra-13265-trun-dtest_stdout.txt,
> cassandra.pb-cache4-dus.2017-02-17-19-36-26.chist.xz,
> cassandra.pb-cache4-dus.2017-02-17-19-36-26.td.xz
>
>
> I observed that sometimes a single node in a Cassandra cluster fails to
> communicate to the other nodes. This can happen at any time, during peak load
> or low load. Restarting that single node from the cluster fixes the issue.
> Before going in to details, I want to state that I have analyzed the
> situation and am already developing a possible fix. Here is the analysis so
> far:
> - A Threaddump in this situation showed 324 Threads in the
> OutboundTcpConnection class that want to lock the backlog queue for doing
> expiration.
> - A class histogram shows 262508 instances of
> OutboundTcpConnection$QueuedMessage.
> What is the effect of it? As soon as the Cassandra node has reached a certain
> amount of queued messages, it starts thrashing itself to death. Each of the
> Thread fully locks the Queue for reading and writing by calling
> iterator.next(), making the situation worse and worse.
> - Writing: Only after 262508 locking operation it can progress with actually
> writing to the Queue.
> - Reading: Is also blocked, as 324 Threads try to do iterator.next(), and
> fully lock the Queue
> This means: Writing blocks the Queue for reading, and readers might even be
> starved which makes the situation even worse.
> -----
> The setup is:
> - 3-node cluster
> - replication factor 2
> - Consistency LOCAL_ONE
> - No remote DC's
> - high write throughput (100000 INSERT statements per second and more during
> peak times).
>
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org
For additional commands, e-mail: commits-h...@cassandra.apache.org
