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Christian Esken edited comment on CASSANDRA-13265 at 4/27/17 1:24 PM: ---------------------------------------------------------------------- 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 | (/) / (?) | No stress-test in build.xml. I patched circle.yml to match that: https://github.com/christian-esken/cassandra/commit/1a776e299c76093eb3edf20e0d9054e14549a667 . CircleCI still kicks off a 4th test, which fails but can likely be ignored for now. | | 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 | was (Author: cesken): 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) | No stress-test in build.xml. I patched circle.yml to match that: https://github.com/christian-esken/cassandra/commit/1a776e299c76093eb3edf20e0d9054e14549a667 | | 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 (100000 INSERT statements per second and more during > peak times). > -- This message was sent by Atlassian JIRA (v6.3.15#6346) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org