[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16197193#comment-16197193 ] ASF GitHub Bot commented on CASSANDRA-13265: Github user christian-esken commented on the issue: https://github.com/apache/cassandra/pull/95 Closing PR, as it has been merged in all relevant banches. See https://issues.apache.org/jira/browse/CASSANDRA-13265 > 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: 3.0.14, 3.11.0, 4.0 > > 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.4.14#64029) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16197194#comment-16197194 ] ASF GitHub Bot commented on CASSANDRA-13265: Github user christian-esken closed the pull request at: https://github.com/apache/cassandra/pull/95 > 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: 3.0.14, 3.11.0, 4.0 > > 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.4.14#64029) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16197195#comment-16197195 ] Christian Esken commented on CASSANDRA-13265: - PR closed: https://github.com/apache/cassandra/pull/95 > 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: 3.0.14, 3.11.0, 4.0 > > 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.4.14#64029) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16195765#comment-16195765 ] ASF GitHub Bot commented on CASSANDRA-13265: Github user jeffjirsa commented on the issue: https://github.com/apache/cassandra/pull/95 Hi @christian-esken , CASSANDRA-13265 has been merged, do you mind closing this PR? (we can't close it for you) > 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: 3.0.14, 3.11.0, 4.0 > > 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.4.14#64029) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15998310#comment-15998310 ] Ariel Weisberg commented on CASSANDRA-13265: I'm sorry :-( I'll try to get a more concrete handle on fix versions earlier next time. It's always been something I've struggled calibrating because different committers are all over the map in terms of how far back they will backport things. > 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: 3.0.14, 3.11.0, 4.0 > > 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 (10 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
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15998277#comment-15998277 ] Christian Esken commented on CASSANDRA-13265: - It is fine, I do not use 2.2. I was just wondering because you asked me to start with 2.2, which required more effort and made things a bit more complicated. If you hadn't asked, I would have done patches just for the HEAD of version 3 (cassandra-3.0) and version 4 (trunk). So, mission complete. Thanks Ariel for guiding me through my first Cassandra patch. :-) > 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: 3.0.14, 3.11.0, 4.0 > > 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 (10 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
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15996951#comment-15996951 ] Ariel Weisberg commented on CASSANDRA-13265: I decided to start from 3.0 because 2.2 is really critical fixes only and this issue has been broken since 2.1 without eliciting a lot of complaints until now. It's a judgement call. I took a quick poll and the response was that 3.0+ was the place to start. Is this something that's impacting you in 2.2? > 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: 3.0.14, 3.11.0, 4.0 > > 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 (10 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
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15996322#comment-15996322 ] Christian Esken commented on CASSANDRA-13265: - Thanks. I have seen your commit in three branches. I did not yet see the changes in cassandra-2.2, when looking at https://github.com/apache/cassandra/commits/cassandra-2.2 . Is this an omission, or is the github repo is not current? > 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: 3.0.14, 3.11.0, 4.0 > > 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 (10 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
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15994820#comment-15994820
]
Christian Esken commented on CASSANDRA-13265:
-
Done. Squashed and pushed.
I also removed my "stress-test" patch in the 3.0 branch, as it is not related
and also does not look like a proper fix. As a reference, here is the patch:
{code}
-- case $CIRCLE_NODE_INDEX in 0) ant eclipse-warnings; ant test ;; 1) ant
long-test ;; 2) ant test-compression ;; 3) ant stress-test ;;esac:
+- case $CIRCLE_NODE_INDEX in 0) ant eclipse-warnings; ant test ;; 1) ant
long-test ;; 2) ant test-compression ;;esac:
{code}
> Expiration in OutboundTcpConnection can block the reader Thread
> ---
>
> Key: CASSANDRA-13265
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13265
> Project: Cassandra
> Issue Type: Bug
> Environment: Cassandra 3.0.9
> Java HotSpot(TM) 64-Bit Server VM version 25.112-b15 (Java version
> 1.8.0_112-b15)
> Linux 3.16
>Reporter: Christian Esken
>Assignee: Christian Esken
> Fix For: 3.0.x
>
> Attachments: cassandra-13265-2.2-dtest_stdout.txt,
> cassandra-13265-trun-dtest_stdout.txt,
> cassandra.pb-cache4-dus.2017-02-17-19-36-26.chist.xz,
> cassandra.pb-cache4-dus.2017-02-17-19-36-26.td.xz
>
>
> I observed that sometimes a single node in a Cassandra cluster fails to
> communicate to the other nodes. This can happen at any time, during peak load
> or low load. Restarting that single node from the cluster fixes the issue.
> Before going in to details, I want to state that I have analyzed the
> situation and am already developing a possible fix. Here is the analysis so
> far:
> - A Threaddump in this situation showed 324 Threads in the
> OutboundTcpConnection class that want to lock the backlog queue for doing
> expiration.
> - A class histogram shows 262508 instances of
> OutboundTcpConnection$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 (10 INSERT statements per second and more during
> peak times).
>
--
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-
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[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ 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 (10 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
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15986786#comment-15986786 ] Ariel Weisberg commented on CASSANDRA-13265: You don't need to get all the tests passing. Only the ones broken specifically by your changes. So you have to run the tests on the base branch (cassandra-2.2, cassandra-3.0, cassandra-3.11, cassandra-trunk). Compare the results to https://builds.apache.org/view/A-D/view/Cassandra/job/Cassandra-2.2-test-all/ or the one specific to the version of your branch. You also need to be aware that a test might just be unreliable in CircleCI. The unit tests seem to be reliable to me when I was running them with my circle.yml, but I am not sure about the one on trunk. Certainly it runs additional tests which weren't running all the time before Circle and I don't think they were reliable when we started running them. > 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.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 (10 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
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15986426#comment-15986426 ] Christian Esken commented on CASSANDRA-13265: - I am fixing the branches, while you work on the dtests. I will continue updating this comment as long as I work on it. || branch || sqaushed? || Unit Tests OK? || comment || | cassandra-13265-3.0 | no | (CircleCI currently running) | | | cassandra-13265-3.11 | no | CircleCI (/) | | | cassandra-13265-2.2 | yes | ant test (/) | CicrleCI hasn't kicked off tests for the branch | | cassandra-13265-trunk | no | CircleCI (?) | My unit test works. Bu there is a strange unrelated unit test failure: ClassNotFoundException: org.apache.cassandra.stress.CompactionStress | > 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.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 (10 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
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15985008#comment-15985008
]
Ariel Weisberg commented on CASSANDRA-13265:
I think the stress-test target just doesn't exist in 3.0.
Adding {{DatabaseDescriptor.daemonInitialization()}} is the correct fix I think.
I a struggling to just get a run of the dtests for 2.2 and trunk before I
merge. This runs output seems corrupted
https://builds.apache.org/view/A-D/view/Cassandra/job/Cassandra-devbranch-dtest/30/
The trunk trunk run doesn't even appear.
> 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.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 (10 INSERT statements per second and more during
> peak times).
>
--
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(v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15981236#comment-15981236
]
Christian Esken commented on CASSANDRA-13265:
-
First here is the summary: The tests work if I add
"DatabaseDescriptor.daemonInitialization();" to the unit test of the affected
branches. Is this a good idea, [~aweisberg]?
Now the long story:
This is the status for branch cassandra-13265-3.0:
- (/) Running unit tests in Eclipse: Works
- (/)/(?) CircleCI: All normal tests work fine. "Your build ran 4754 tests in
junit with 0 failures". The build fails for me with: Target "stress-test" does
not exist in the project "apache-cassandra". As "ant test" worked, I would
guess that the patch is fine. I will reverify the specific unit test locally
This is the status for branch cassandra-13265-3.11 and cassandra-13265-trunk:
- (/) Running unit tests in Eclipse: Works
- (x) Running unit tests with CircleCI or "ant test" fails, due to
non-initialized DatabaseDescriptor.
When I add the following to the unit test of cassandra-13265-3.11, the unit
test works.
{code}
DatabaseDescriptor.daemonInitialization();
{code}
{code}
[junit] Null Test: Caused an ERROR
[junit] null
[junit] java.lang.ExceptionInInitializerError
[junit] at java.lang.Class.forName0(Native Method)
[junit] at java.lang.Class.forName(Class.java:264)
[junit] Caused by: java.lang.NullPointerException
[junit] at
org.apache.cassandra.config.DatabaseDescriptor.getWriteRpcTimeout(DatabaseDescriptor.java:1400)
[junit] at
org.apache.cassandra.net.MessagingService$Verb$1.getTimeout(MessagingService.java:121)
[junit] at
org.apache.cassandra.net.OutboundTcpConnectionTest.(OutboundTcpConnectionTest.java:43)
{code}
> Expiration in OutboundTcpConnection can block the reader Thread
> ---
>
> Key: CASSANDRA-13265
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13265
> Project: Cassandra
> Issue Type: Bug
> Environment: Cassandra 3.0.9
> Java HotSpot(TM) 64-Bit Server VM version 25.112-b15 (Java version
> 1.8.0_112-b15)
> Linux 3.16
>Reporter: Christian Esken
>Assignee: Christian Esken
> Fix For: 3.0.x
>
> Attachments: cassandra.pb-cache4-dus.2017-02-17-19-36-26.chist.xz,
> cassandra.pb-cache4-dus.2017-02-17-19-36-26.td.xz
>
>
> I observed that sometimes a single node in a Cassandra cluster fails to
> communicate to the other nodes. This can happen at any time, during peak load
> or low load. Restarting that single node from the cluster fixes the issue.
> Before going in to details, I want to state that I have analyzed the
> situation and am already developing a possible fix. Here is the analysis so
> far:
> - A Threaddump in this situation showed 324 Threads in the
> OutboundTcpConnection class that want to lock the backlog queue for doing
> expiration.
> - A class histogram shows 262508 instances of
> OutboundTcpConnection$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 (10 INSERT statements per second and more during
> peak times).
>
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15978748#comment-15978748 ] Christian Esken commented on CASSANDRA-13265: - I pulled the changes, fixed the CHANGES.txt and pushed everything again. Now CircleCI is kicking off the builds for the branches. Looks like we are getting somewhere. :-) > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15978730#comment-15978730 ] Christian Esken commented on CASSANDRA-13265: - Hmm, I rebased on 2.2 and trunk. I am surprised that 3.11 is not current, as 3.11 is not that old. I will now clean my repo, including deleting the bad "13625" branches and rebasing 3.0 and 3.11. > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15977067#comment-15977067 ] Ariel Weisberg commented on CASSANDRA-13265: The branches are out of date. 3.11 ones doesn't have a circle.yml. They really need to be rebased onto something relatively recent so they can run in Circle. > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15976867#comment-15976867 ] Ariel Weisberg commented on CASSANDRA-13265: That circle.yml is broken. For instance OutboundTcpConnectionTest failed to start because it NPEed in DatabaseDescriptor but it's not in the summary. Or maybe it's Circle. I'm not sure. I'm also not sure why your are only getting builds for trunk. If you fix the unit test I think it's ready to commit. The dtests ran on Apache Jenkins for everything except trunk. Trunk timed out on one test so I'm going to try it again. > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15976279#comment-15976279 ] Christian Esken commented on CASSANDRA-13265: - Unfortunately some test failed, not because of bugs but due to technical issues, mostly with "com.datastax.driver.core.exceptions.NoHostAvailableException". Are these the "dtest" issues in CircleCI you mentioned? I tried to run the tests locally, but even "ant test" runs > 1 hour and keeps failing with Timeout, NoHostAvailableException, or similar. I don't know why the tests fail, as my Laptop should be capable of doing it. I am frequently running a 3-node Cassandra on it via ccm and that works properly. Currently I think I did all I can do. Let me know if I can check something else. What is your proposal how do we continue here? > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15974885#comment-15974885 ] Christian Esken commented on CASSANDRA-13265: - No problem. I was away for Easter, so I did not even notice you being busy. I just started my CircleCI test for the first time. Its working on the first branch (trunk) for an hour and is not complete yet, so I guess with all the branches it can take a day to complete. I have restarted the build with more parallelism and will send an update whenever that is complete. Hopefully that will create a more acceptable turnaround time. https://circleci.com/gh/christian-esken/cassandra/3 > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15974671#comment-15974671 ] Ariel Weisberg commented on CASSANDRA-13265: Sorry I just had a really busy week last week and I've been trying to get Circle to the point it can run the dtests. I'm mostly there it's just a few failing tests that remain. > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15974590#comment-15974590 ] Christian Esken commented on CASSANDRA-13265: - bq. For CHANGES.TXT the entry should go at the top of the list of entries for the version the change is for. I don't know why. I also haven't seen this mentioned. Probably someone could add that to https://wiki.apache.org/cassandra/HowToContribute or http://cassandra.apache.org/doc/latest/development/how_to_commit.html . Anyhow I have fixed that. bq. set up with CircleCI [...] Also you transposed 13625 and 13265 I changed the branches to correct the transposing 13625 and 13265. I didn't find any other place than the branch names. I will try to find out about how to do the CircleCI stuff. Meanwhile here are the updated links: https://github.com/christian-esken/cassandra/commits/cassandra-13265-2.2 https://github.com/christian-esken/cassandra/commits/cassandra-13265-3.0 https://github.com/christian-esken/cassandra/commits/cassandra-13265-3.11 https://github.com/christian-esken/cassandra/commits/cassandra-13265-trunk > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15967870#comment-15967870 ] Ariel Weisberg commented on CASSANDRA-13265: Nevermind I'll run them. I have to anyways for the dtests until we get the dtests running in CircleCI. I updated my copies. For CHANGES.TXT the entry should go at the top of the list of entries for the version the change is for. I don't know why. > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15967857#comment-15967857 ] Ariel Weisberg commented on CASSANDRA-13265: OK, don't forget to get set up with CircleCI and post the block with the test results. Also you transposed 13625 and 13265 :-) > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15967484#comment-15967484 ] Christian Esken commented on CASSANDRA-13265: - There were different reasons why the build failed, e.g. somehow Eclipse did not pick up the build parameters for 2.2 after "ant generate-eclipse-files" and the build was done with Java 8 language level (lambdas). Looks like building and testing in Eclipse alone is not enough, so I redid everything manually in the console and fixed the issues. As you recommended, I have created branches that follow your naming (cassandra-13625-3.0) with squashed commits. The new branches are: https://github.com/christian-esken/cassandra/commits/cassandra-13625-2.2 https://github.com/christian-esken/cassandra/commits/cassandra-13625-3.11 https://github.com/christian-esken/cassandra/commits/cassandra-13625-3.0 https://github.com/christian-esken/cassandra/commits/cassandra-13625-trunk About CHANGES.TXT: I added changes to all branches where in the appropriate versions. Please check, as the naming conventions within Cassandra are still not clear to me(e.g. there exists a 3.11 branch, a 3.0.11 release and a 3.11.0 changelog entry). > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15964943#comment-15964943 ] Ariel Weisberg commented on CASSANDRA-13265: There seem to be some build issues in various branches? Maybe because I rebased? You should register with CircleCI so it will automatically build and run the unit tests for you out of your repo when you commit. ||Code|utests|dtests|| |[2.2|https://github.com/aweisberg/cassandra/pull/new/cassandra-13265-2.2]|[utests|https://circleci.com/gh/aweisberg/cassandra/tree/cassandra-13265-2%2E2]|| |[3.0|https://github.com/aweisberg/cassandra/pull/new/cassandra-13265-3.0]|[utests|https://circleci.com/gh/aweisberg/cassandra/tree/cassandra-13265-3%2E0]|| |[3.11|https://github.com/aweisberg/cassandra/pull/new/cassandra-13265-3.11]|[utests|https://circleci.com/gh/aweisberg/cassandra/tree/cassandra-13265-3%2E11]|| |[trunk|https://github.com/aweisberg/cassandra/pull/new/cassandra-13265-trunk]|[utests|https://circleci.com/gh/aweisberg/cassandra/tree/cassandra-13625-trunk]|| > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15964613#comment-15964613 ] Ariel Weisberg commented on CASSANDRA-13265: Squashing is preferred, but I like to keep the history. When I squash I create a second -squashed branch to hold the squash commit. I never delete branches and tolerate the cluttered namespace. If we used pull requests I would delete branches since the pull request preserves the information, but we don't :-( Since people tend to work on multiple tickets they don't name the branch cassandra-3.0 they do something like cassandra-13625-3.0. The commit process I follow is http://cassandra.apache.org/doc/latest/development/how_to_commit.html. For the commit message don't list multiple reviewers just the one in the JIRA (me). I have been told that line is automatically parsed so we want to stick to the expected format. Also some OCD people want a line break in between the first and last line of the commit message. Having CHANGES.TXT in the patch is helpful so I don't forget to add it in one branch. If it's not there and I follow the commit process I have to add it at each branch. For the entry also include the ticket number in parens at the end. I'll kick off the tests now. > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15964522#comment-15964522 ] Christian Esken commented on CASSANDRA-13265: - Done. 2 organizational topics left: I will add the required line to the commit message. Looks OK?!? bq. patch by Christian Esken; reviewed by Ariel Weisberg and Jason Brown for CASSANDRA-13265 My proposals for the CHANGES.txt would be the following text. Can you do that, Ariel? I do not know in which versions to add that, as they are upcoming versions. bq. Expire OutboundTcpConnection messages by a single Thread Here are the branches.The cassandra-3.0 is already squashed. If that branch is OK, I will also squash the other 3 branches. https://github.com/christian-esken/cassandra/commits/cassandra-3.0 https://github.com/christian-esken/cassandra/commits/cassandra-3.11 https://github.com/christian-esken/cassandra/commits/trunk https://github.com/christian-esken/cassandra/commits/cassandra-2.2 > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15963230#comment-15963230 ] Ariel Weisberg commented on CASSANDRA-13265: Great! Most regular contributors are linking to a branch in their fork, but there are issues with that (people force update, delete branches). You don't have to attach a patch to get it to submit patch. I do need a patch for each branch. 2.2, 3.0, 3.11 and trunk. We try to push the work of dealing with the merge conflicts to the assignees over the committers. Use whatever method you prefer to submit the code. When you have all of the patches I'll kick off test runs. It's going to take a while for the dtests to run right now. > 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.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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15963095#comment-15963095 ] Christian Esken commented on CASSANDRA-13265: - Done. My highest priority is the 3.0 branch. I created a patch (single file, squashed) for 3.0, that I also applied to my Github fork https://github.com/christian-esken/cassandra/commits/cassandra-3.0 . Please have a look at the attached file 0001-3.0-Expire-OTC-messages-by-a-single-Thread.patch . > 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: 2.2.x, 3.0.x, 3.11.x, 4.x > > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15928300#comment-15928300 ] Ariel Weisberg commented on CASSANDRA-13265: Great! Almost there. * [Use Config.PROPERTY_PREFIX with the property name.|https://github.com/apache/cassandra/pull/95/files#diff-c7ef124561c4cde1c906f28ad3883a88R139] * [Still using big I integer here.|https://github.com/apache/cassandra/pull/95/files#diff-71f06c193f5b5e270cf8ac695164f43aR2685] * [And here.|https://github.com/apache/cassandra/pull/95/files#diff-097eb77c5d9d80a48e7547fbb81822caR62] After that the last step is to create 2.2, 3.0, and 3.11 branches. Then I'll run the tests for each of the branches and if they look good I'll commit. > 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: 2.2.x, 3.0.x, 3.11.x, 4.x > > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15926348#comment-15926348
]
Christian Esken commented on CASSANDRA-13265:
-
bq. I still think it's a good idea to avoid hard coding this kind of value so
operators have options without recompiling. [...] A java property.
(/) static final int BACKLOG_PURGE_SIZE =
Integer.getInteger("OTC_BACKLOG_PURGE_SIZE", 1024);
bq. I think we should log the drops especially due to timeouts as they happen
rather than at the end.
(/) I agree, and I did not change that. After the loop I simply add the
unprocessed messages, which happen due to {{break inner;}}. I'll push today, so
you have a chance to see that.
> 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: 2.2.x, 3.0.x, 3.11.x, 4.x
>
> Attachments: 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 (10 INSERT statements per second and more during
> peak times).
>
--
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(v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15926015#comment-15926015
]
Ariel Weisberg commented on CASSANDRA-13265:
bq. I see. I thought it would just clutter the cassanda.yaml, as nobody ever
would change the value. But if you feel it is important enough, I can do so.
So not a property in the YAML. A java property. So something like
"Integer.getInteger("property", 1024);" instead of just "1024".
bq. PS: I will be soon on vacation for two weeks, so please don't wonder why
you do not see any updates from me.
Enjoy
> 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: 2.2.x, 3.0.x, 3.11.x, 4.x
>
> Attachments: 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 (10 INSERT statements per second and more during
> peak times).
>
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15925815#comment-15925815 ] Christian Esken commented on CASSANDRA-13265: - bq. it's very low effort to add a property I see. I thought it would just clutter the cassanda.yaml, as nobody ever would change the value. But if you feel it is important enough, I can do so. bq. Not a huge deal, but I think we should log the drops especially due to timeouts as they happen OK. I can follow your argument. I will rewrite it, also adding comments with explanation. PS: I will be soon on vacation for two weeks, so please don't wonder why you do not see any updates from me. > 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: 2.2.x, 3.0.x, 3.11.x, 4.x > > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15924658#comment-15924658 ] Ariel Weisberg commented on CASSANDRA-13265: bq. I still think it's a good idea to avoid hard coding this kind of value so operators have options without recompiling. I would like BACKLOG_PURGE_SIZE to be kept hard coded for now. It has been there for quite some time hard coded, and in the long term I do not think it should be kept as-is. For example it would better to purge on the number of actually DROPPABLE messages in the queue (or their weight if you want to extend even further) I agree but I don't want to add more to this change set and I want to backport it to at least 2.2. I suggest it primarily because it's very low effort to add a property as opposed to a full YAML + JMX config option. bq. At Github? I can do so. But no PR, right? I saw it mentioned that one should not open PR's for Cassandra on Github as they cannot be handled (it's just a mirror). Project policy is to not use PRs even for comments. Code review comments go in JIRA. What I and some others do is link to a compare view of what we intend to merge. Don't delete the branches your links point to because it invalidates the information in JIRA. bq. I looked in more detail, and I think this a flaw in the original code "suggested" me to do this: drainedMessages.clear() is called twice, and one time would be enough. IMO it would be better to only keep the one at the end of the method and also do the drop-counting for the drained messages there. This would also cover a rather exotic case of the catch (Exception e) in the run() method. If an Exception is thrown, then there is a danger of nothing being counted. So there is the issue of not counting drops as they happen. The thread can block for a long time writing messages so if we wait to count drops they won't show up quite as promptly. Not a huge deal, but I think we should log the drops especially due to timeouts as they happen rather than at the end. It's definitely true that we don't need to clear the backlog twice and we could log the drops due to items remaining in the backlog there. The loop decrements a counter every time it runs so you know how many remaining elements are being dropped if you hit break inner. > 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: 2.2.x, 3.0.x, 3.11.x, 4.x > > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15924135#comment-15924135 ] Christian Esken commented on CASSANDRA-13265: - Marking off feedback: - (/) A smaller value could potentially ... - (/) You shouldn't need the check for null? Usually we "just" make sure its not null OK. I thought it might be possible to set this to null, but even JConsole refuses it. - (/) Using a boxed integer makes it a bit confusing ... ACK. Happily changed that. Looks like I followed bad examples. - (/) Avoid unrelated whitespace changes. OK. I missed that after moving the field. - (x) I still think it's a good idea to avoid hard coding this kind of value so operators have options without recompiling. - (/) Fun fact. You don't need backlogNextExpirationTime to be volatile. You can piggyback on backlogExpirationActive to get the desired effects from the Java memory model. [...] I wouldn't change it ... Yes. I am aware of that and using that technique often. Here I did not like it as visibility effects would not be obvious, unless explicitly documented. You are probably aware what Brian Goetz says about piggybacking in his JCIP book. BTW: A more obvious usage is for me in status fields, e.g. to make the results of a Future visible. I won't change it either, so marking this as done. - (x)Breaking out the uber bike shedding this could be maybeExpireMessages. - (x)Swap the order of these two stores so it doesn't do extra expirations. Ouch. That hurts. I was quite tired yesterday. :-| - (?) This is not quite correct you can't count drainCount as dropped because some of the drained messages may have been sent during iteration. In progress. I am wondering if we should include fixing the drop count it in this patch, as it will likely create even more conflicts. OTOH I have to touch some related methods anyhow. I will think about it. > 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: 2.2.x, 3.0.x, 3.11.x, 4.x > > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15923915#comment-15923915
]
Christian Esken commented on CASSANDRA-13265:
-
bq. This is not quite correct you can't count drainCount as dropped because
some of the drained messages may have been sent during iteration.
I looked in more detail, and I think this a flaw in the original code
"suggested" me to do this: {{drainedMessages.clear()}} is called twice, and
one time would be enough. IMO it would be better to only keep the one at the
end of the method and also do the drop-counting for the drained messages there.
This would also cover a rather exotic case of the {{catch (Exception e)}} in
the {{run()}} method. If an Exception is thrown, then there is a danger of
nothing being counted.
bq. Using a boxed integer
bq. You shouldn't need the check for null?
>From a brief check, this refers to a similar point. I saw many configuration
>options to allow null and followed that route. I am absolutely happy to make
>it non-boxed.
bq. The right way to do it is create a branch for all the versions where this
is going to be fixed. Start at 2.2, merge to 3.0, merge to 3.11, then merge to
trunk.
At Github? I can do so. But no PR, right? I saw it mentioned that one should
not open PR's for Cassandra on Github as they cannot be handled (it's just a
mirror).
> 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: 2.2.x, 3.0.x, 3.11.x, 4.x
>
> Attachments: 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 (10 INSERT statements per second and more during
> peak times).
>
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15908545#comment-15908545
]
Ariel Weisberg commented on CASSANDRA-13265:
The right way to do it is create a branch for all the versions where this is
going to be fixed. Start at 2.2, merge to 3.0, merge to 3.11, then merge to
trunk.
You can get away with one field. Check the next expiration time, CAS it to
{{Long.MAX_VALUE}}, then when you are done store the next expiration time in
it. Doing it with two fields also works. I wouldn't bother changing it.
If you set the default value via a property it will work fine. It will set it
once when it loads the class at startup and then overwrite it with YAML
contents or JMX invocations. Generally we do set the default value in config
via assignment. Doing it via property gives yet another way to set the value,
but it's the least important. It's more useful for things which aren't in the
YAML. Adding YAML properties adds a bit of boiler plate.
* [A smaller value could potentially expire messages slightly sooner at the
expense of more CPU time and queue contention while iterating the backlog of
messages.
* [You shouldn't need the check for null? Usually we "just" make sure its not
null and skip the
boilerplate.|https://github.com/apache/cassandra/pull/95/files#diff-a8a9935b164cd23da473fd45784fd1ddR1973]
* [Avoid unrelated whitespace changes.|
https://github.com/apache/cassandra/pull/95/files#diff-a8a9935b164cd23da473fd45784fd1ddL2034]
* [I still think it's a good idea to avoid hard coding this kind of value so
operators have options without
recompiling.|https://github.com/apache/cassandra/pull/95/files#diff-c7ef124561c4cde1c906f28ad3883a88R139]
* Fun fact. You don't need {{backlogNextExpirationTime}} to be volatile. You
can piggyback on {{backlogExpirationActive}} to get the desired effects from
the Java memory model. A store to {{backlogExpirationActive}} makes a prior
stores (by the current thread) to {{backlogNextExpirationTime}} visible. A read
of {{backlogExpirationActive}} would make prior stores to
{{backlogNextExpirationTimeVisible}} by the last writer to
{{backlogExpirationActive}} visible. The volatile read is close to free so I
wouldn't change it just so it's not sensitive to the order the fields are
accessed in.
* [Breaking out the uber bike shedding this could be
maybeExpireMessages.|https://github.com/apache/cassandra/pull/95/files#diff-c7ef124561c4cde1c906f28ad3883a88R600]
* [Swap the order of these two stores so it doesn't do extra
expirations.|https://github.com/apache/cassandra/pull/95/files#diff-c7ef124561c4cde1c906f28ad3883a88R636]
* [Using a boxed integer makes it a bit confusing because now everyone has to
know how null is handled. What's the diff between null and 0? Better to let 0
be disabled and not have
null.|https://github.com/apache/cassandra/pull/95/files#diff-097eb77c5d9d80a48e7547fbb81822caR62]
* [This is not quite correct you can't count drainCount as dropped because some
of the drained messages may have been sent during
iteration.|https://github.com/apache/cassandra/pull/95/files#diff-c7ef124561c4cde1c906f28ad3883a88R270]
> 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: 2.2.x, 3.0.x, 3.11.x, 4.x
>
> Attachments: 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
> writ
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15907493#comment-15907493 ] Christian Esken commented on CASSANDRA-13265: - The change is now finished, including configuration, MBean and testing. I also tested an interval of 0 ms, which is close to what Cassandra does today. Please have a look. What is the recommended way of getting this into the official Cassandra repo? A patch, or would someone with write access take it directly from Github? This also has impact on how the merge conflicts will be resolved, as there are now 3 files with conflicts e branch has now merge conflicts on 3 files according to https://github.com/apache/cassandra/pull/95. I did not want to rebase my branch without asking. > 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 > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15905409#comment-15905409 ] Christian Esken commented on CASSANDRA-13265: - I committed the change containing the configuration, as I would like some feedback whether I am on the right path. Please note that I did not yet have time for tests (planned for next Monday), but I thought it is better to give a chance to review the current changes. Please note that I had to add back "AtomicBoolean backlogExpirationActive" Otherwise I cannot guarantee that only a single Thread is iterating the Queue, especially if a small expiration interval (1ms, or 0ms) is configured. The "AtomicLong backlogNextExpirationTime" could now be "volatile long". > 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 > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15904949#comment-15904949
]
Christian Esken commented on CASSANDRA-13265:
-
I am nearly done with the configuration, and have two questions about it:
1. How to handle the default value? My approach is to pre-configure the
default value in Config:
{code}
public static final int otc_backlog_expiration_interval_in_ms_default = 200;
public volatile Integer otc_backlog_expiration_interval_in_ms =
otc_backlog_expiration_interval_in_ms_default;
{code}
- Additionally I will handle null values, that might come in via MBean in the
getter of DatabaseDescriptor:
{code}
public static Integer getOtcBacklogExpirationInterval()
{
Integer confValue = conf.otc_backlog_expiration_interval_in_ms;
return confValue != null ? confValue :
Config.otc_backlog_expiration_interval_in_ms_default;
}
{code}
2. How to read the config value? I am seeing some Integer.getInteger(propName,
defaultValue), but this looks strange to me. I think changes from JMX would not
even be reflected. Thus I am calling the getter from above:
{{DatabaseDescriptor.getOtcBacklogExpirationInterval()}}. Is thte latter OK?
> 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
> Attachments: 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 (10 INSERT statements per second and more during
> peak times).
>
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[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15901495#comment-15901495 ] Christian Esken commented on CASSANDRA-13265: - I pushed the changes noted in the former comment. I am plannig to do "Configurabilty and default value" tomorrow. > 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 > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15901414#comment-15901414 ] Christian Esken commented on CASSANDRA-13265: - I will update the status while working on the individual topics: (x)This needs to be configurable from the YAML and via JMX. (/)It should include drained messages as well. (/)Typo, "thus letting" (/)Extra line break (/)We don't do/allow author tags (x)Use TimeUnit (x)It isn't using the constant. (x)Just in case maybe assert the droppable/non-droppable status of the verbs. Or does it not matter since the tests will fail anyways? > 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 > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15901047#comment-15901047 ] Christian Esken commented on CASSANDRA-13265: - bq. It should include drained messages as well OMG, right. I thought about that concluded it is correct to exclude. But obviously the messages are already drained from the queue, so they must be added. bq. We don't do/allow author tags OOPS, always this oversmart IDE :-) bq. This needs to be configurable Oh. Even more work. This is getting bigger than anticipated, but I am happy to do it. Thanks for the hints on how do do the Configuration. I will work on it later this day or tomorrow. > 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 > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=1595#comment-1595
]
Ariel Weisberg commented on CASSANDRA-13265:
Awesome.
* [This needs to be configurable from the YAML and via JMX. Add it to
{{StorageProxyMBean}}/{{StorageProxy}}, store the value in {{Config}} then get
it from {{DatabaseDescriptor}} it will need to be a volatile field in
{{Config}}. Add a setter and a getter. I have the setter return the previous
value, but a lot of the existing ones don't. 10 seconds is also way too high as
a default. I propose 200 milliseconds. It's an improvement over today, but
still aggressive at trying to free memory. Also use
{{java.util.concurrent.TimeUnit}} to convert to the value you
want.|https://github.com/apache/cassandra/pull/95/files#diff-c7ef124561c4cde1c906f28ad3883a88R134]
* [It should include drained messages as well. To be 100% correct you would
have to count how many messages you have iterated over and sent and then
subtract.|https://github.com/apache/cassandra/pull/95/files#diff-c7ef124561c4cde1c906f28ad3883a88R261]
* [Typo, "thus
letting"|https://github.com/apache/cassandra/pull/95/files#diff-c7ef124561c4cde1c906f28ad3883a88R604]
* [Extra line
break|https://github.com/apache/cassandra/pull/95/files#diff-c7ef124561c4cde1c906f28ad3883a88R625]
* [We don't do/allow author
tags|https://github.com/apache/cassandra/pull/95/files#diff-c16fff43d2aafe61a4219656d1ab6f9eR26]
* [Use
TimeUnit|https://github.com/apache/cassandra/pull/95/files#diff-c16fff43d2aafe61a4219656d1ab6f9eR36]
* [It isn't using the
constant.|https://github.com/apache/cassandra/pull/95/files#diff-c16fff43d2aafe61a4219656d1ab6f9eR118]
* [Just in case maybe assert the droppable/non-droppable status of the verbs.
Or does it not matter since the tests will fail
anyways?|https://github.com/apache/cassandra/pull/95/files#diff-c16fff43d2aafe61a4219656d1ab6f9eR33]
I had a sad and unfortunate thought. We are going about expiring wrong by
counting messages. We really want to expire based on the weight of the queue.
Also I really really hate that bounded queues that aren't weighted are a thing.
Let's not do that here though since I want to backport this to other versions.
> 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
> Attachments: 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 (10 INSERT statements per second and more during
> peak times).
>
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[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15899773#comment-15899773 ] Christian Esken commented on CASSANDRA-13265: - I added three changes: - Implemented unit test - Count dropped messages if Cassandra cannot write to the socket - Fix the QueuedMessage.isTimedOut(), which was prone to a System.nanoTime() wrap bug, as it used a check of type: aNanos < bNanos > 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 > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15898266#comment-15898266 ] Jason Brown commented on CASSANDRA-13265: - bq. we were supposed to mark those as dropped We probably should count them as dropped as we are dropping them, huh ;) fwiw, looks like it's always been implemented this way, since CASSANDRA-3005 > 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 > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[ https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15898249#comment-15898249 ] Ariel Weisberg commented on CASSANDRA-13265: I think you are correct that we were supposed to mark those as dropped. [~jasobrown] do you agree? I think the approximate nanoTime/currenTimeMillis approach where a single thread periodically updates the time is reasonable. If you added nanoTime to ApproximateTime with it's own configuration I think it would be fine to use it in this context. > 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 > Attachments: 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 (10 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346)
[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15897641#comment-15897641
]
Christian Esken commented on CASSANDRA-13265:
-
I have one question about a code fragment. When the socket is not available the
backlog is cleared, but no drops are counted. Looks like an omission to me, or
is it intentional? {{dropped.addAndGet(backlog.size(); )}} would be an
approximation. We likely cannot get closer as {{backlog.clear();}} does not
tell how much elements were removed.
{code}
if (qm.isTimedOut())
dropped.incrementAndGet();
else if (socket != null || connect())
writeConnected(qm, count == 1 && backlog.isEmpty());
else
{
// clear out the queue, else gossip messages back up.
drainedMessages.clear();
// dropped.addAndGet(backlog.size()); // TODO Should
dropped statistics be counted in this case?
backlog.clear();
break inner;
}
{code}
> 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
> Attachments: 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 (10 INSERT statements per second and more during
> peak times).
>
--
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[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15897121#comment-15897121
]
Christian Esken commented on CASSANDRA-13265:
-
I was already looking into doing a unit test it but it requires access to the
queue which means making it package level access and using
{{@VisibleForTesting}}. I will do that tomorrow, unless there are arguments
against it.
> 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
> Attachments: 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 (10 INSERT statements per second and more during
> peak times).
>
--
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[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15894783#comment-15894783
]
Jason Brown commented on CASSANDRA-13265:
-
I'm +1 on the ticket, but [~aweisberg] should also weigh in.
As a note, we have {{ApproximateTime}} for an estimated time, but that works
off of {{System.currentTimeMillis()}} rather than {{System.nanoTime()}}, so
monotonicity.
> 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
> Attachments: 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 (10 INSERT statements per second and more during
> peak times).
>
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[jira] [Commented] (CASSANDRA-13265) Expiration in OutboundTcpConnection can block the reader Thread
[
https://issues.apache.org/jira/browse/CASSANDRA-13265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15894000#comment-15894000
]
Christian Esken commented on CASSANDRA-13265:
-
Your "nit" totally makes sense, as {{nanoTime()}} is expensive if called very
often. Good catch, actually I should have seen that myself. I committed the
change, including the required change to RetriedQueuedMessage. I also removed
two warnings by adding the generic types.
As a side note, one could even use an estimated time here, like
EstimatorTimeSource which works with a regularly updated cached time. I was
able to boost the performance of Triava Cache by factor 2 - 10 depending on the
test. An example is in
https://github.com/trivago/triava/blob/master/src/examples/java/com/trivago/examples/TimeSourceExample.java,
estimatorTimeSource().
> 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
> Attachments: 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 (10 INSERT statements per second and more during
> peak times).
>
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