[ 
https://issues.apache.org/jira/browse/CASSANDRA-9573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14581696#comment-14581696
 ] 

Benedict commented on CASSANDRA-9573:
-------------------------------------

Ah, I forgot we used the jna Native class now.

I've pushed a branch with a teensy change 
[here|https://github.com/belliottsmith/cassandra/tree/9573], that just runs the 
startup checks before mlockall. If that passes we've found our culprit. 

It isn't a final patch; I'll leave that to Sam, if it is indeed the problem, 
since CASSANDRA-8049 would be the real culprit (without CASSANDRA-9240 it would 
just happen a little less - a large enough bloom filter would cause the same 
issue)

> OOM when loading compressed sstables (system.hints)
> ---------------------------------------------------
>
>                 Key: CASSANDRA-9573
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9573
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Alan Boudreault
>            Assignee: Benedict
>            Priority: Critical
>             Fix For: 2.2.0 rc2
>
>         Attachments: hs_err_pid11243.log, 
> java-hints-issue-2015-06-09.snapshot, system.log, yourkit.ss.tar.gz
>
>
> [~andrew.tolbert] discovered an issue while running endurance tests on 2.2. A 
> Node was not able to start and was killed by the OOM Killer.
> Briefly, Cassandra use an excessive amount of memory when loading compressed 
> sstables (off-heap?). We have initially seen the issue with system.hints 
> before knowing it was related to compression. system.hints use lz4 
> compression by default. If we have a sstable of, say 8-10G, Cassandra will be 
> killed by the OOM killer after 1-2 minutes. I can reproduce that bug 
> everytime locally. 
> * the issue also happens if we have 10G of data splitted in 13MB sstables.
> * I can reproduce the issue if I put a lot of data in the system.hints table.
> * I cannot reproduce the issue with a standard table using the same 
> compression (LZ4). Something seems to be different when it's hints?
> You wont see anything in the node system.log but you'll see this in 
> /var/log/syslog.log:
> {code}
> Out of memory: Kill process 30777 (java) score 600 or sacrifice child
> {code}
> The issue has been introduced in this commit but is not related to the 
> performance issue in CASSANDRA-9240: 
> https://github.com/apache/cassandra/commit/aedce5fc6ba46ca734e91190cfaaeb23ba47a846
> Here is the core dump and some yourkit snapshots in attachments. I am not 
> sure you will be able to get useful information from them.
> core dump: http://dl.alanb.ca/core.tar.gz
> Not sure if this is related, but all dumps and snapshot points to 
> EstimatedHistogramReservoir ... and we can see many 
> javax.management.InstanceAlreadyExistsException: 
> org.apache.cassandra.metrics:... exceptions in system.log before it hangs 
> then crash.
> To reproduce the issue: 
> 1. created a cluster of 3 nodes
> 2. start the whole cluster
> 3. shutdown node2 and node3
> 4. writes 10-15G of data on node1 with replication factor 3. You should see a 
> lot of hints.
> 5. stop node1
> 6. start node2 and node3
> 7. start node1, you should OOM.
> //cc [~tjake] [~benedict] [~andrew.tolbert]



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to