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https://issues.apache.org/jira/browse/CASSANDRA-10821?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15044839#comment-15044839
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Thom Bartold commented on CASSANDRA-10821:
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After restarting again yesterday, one of 6 nodes has started compacting
regularly and is down to a few hundred pending. The other 5 are still working
on the same one.
e.g. The node mentioned above appears to still be working on the same
compaction, but with a different id.
pending tasks: 1095
id compaction type keyspace
table completed total unit progress
70583ff0-9cba-11e5-8c41-ffef1041ec45 Compaction overlordpreprod
document 323082945806 839129219651 bytes 38.50%
Active compaction remaining time : n/a
> OOM Killer terminates Cassandra when Compactions use too much memory then
> won't restart
> ---------------------------------------------------------------------------------------
>
> Key: CASSANDRA-10821
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10821
> Project: Cassandra
> Issue Type: Bug
> Components: Compaction
> Environment: EC2 32 x i2.xlarge split between us-east-1a,c and
> us-west 2a,b
> Linux 4.1.10-17.31.amzn1.x86_64 #1 SMP Sat Oct 24 01:31:37 UTC 2015 x86_64
> x86_64 x86_64 GNU/Linux
> Java(TM) SE Runtime Environment (build 1.8.0_65-b17)
> Java HotSpot(TM) 64-Bit Server VM (build 25.65-b01, mixed mode)
> Cassandra version: 2.2.3
> Reporter: Thom Bartold
>
> We were writing to the DB from EC2 instances in us-east-1 at a rate of about
> 3000 per second, replication us-east:2 us-west:2, LeveledCompaction and
> DeflateCompressor.
> After about 48 hours some nodes had over 800 pending compactions and a few of
> them started getting killed for Linux OOM. Priam attempts to restart the
> nodes, but they fail because of corrupted saved_cahce files.
> Loading has finished, and the cluster is mostly idle, but 6 of the nodes were
> killed again last night by OOM.
> This is the log message where the node won't restart:
> ERROR [main] 2015-12-05 13:59:13,754 CassandraDaemon.java:635 - Detected
> unreadable sstables /media/ephemeral0/cassandra/saved_caches/KeyCache-ca.db,
> please check NEWS.txt and ensure that you have upgraded through all required
> intermediate versions, running upgradesstables
> This is the dmesg where the node is terminated:
> [360803.234422] Out of memory: Kill process 10809 (java) score 949 or
> sacrifice child
> [360803.237544] Killed process 10809 (java) total-vm:438484092kB,
> anon-rss:29228012kB, file-rss:107576kB
> This is what Compaction Stats look like currently:
> pending tasks: 1096
> id compaction type keyspace
> table completed total unit progress
> 93eb3200-9b58-11e5-b9f1-ffef1041ec45 Compaction overlordpreprod
> document 8670748796 839129219651 bytes 1.03%
> Compaction system
> hints 30 1921326518 bytes 0.00%
> Active compaction remaining time : 27h33m47s
> Only 6 of the 32 nodes have compactions pending, and all on the order of 1000.
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