Re: Irresponsive nodes

Fri, 09 Oct 2009 05:11:49 -0700 

Thanks for the tips Eric.
I was just about to try it, when I noticed, it had become responsive again. 
It took exactly 1 hour, before it was done!...

But when I restart now, it's ready almost immediatly... Weird stuff!!

I will try out your tips, next time this happens!
It sounds like, it's pretty well-defined, when the JVM dies under GC load..? 
Any pointers there?
I was just thinking, that it might be possible, to add nodes based on current knowledge? 

#Dan

On 09/10/2009, at 13.58, Eric Bowman wrote:


A few things to try:
1. Enable verbose GC logging to see if your JVM is dying under GC load. 
2. pkill -3 java will dump some nice stack traces from all running
threads, could be some clues there.


Dan Larsen wrote:

Hi again :-)

O.k... New problem...
I have an Amazon EC2 node with 4 "CPUs" and 7.5 GB of RAM.
Running CommitLog on 1 disk and data on another.
Cassandra 0.4.0 - (yes I have checked... correct version :-P)
6GB set in the cassandra.in.sh.

I started throwing data at it, without problems.
All of a sudden, the node becomes irresponsive.

I only have 6.6GB of data in the DBs.

I experienced the same thing, while running much smaller nodes.

I tried restarting cassandra (kill [pid]).

When it starts up, it goes crazy for a while, trying to fill up the
RAM or something.
Then it stops filling RAM, but keeps a load of ~100% CPU.
It doesn't respond to anything, but a nodeprobe info, which responds,
but VERY slowly.
The log doesn't give me anything - not that I can understand anyways... 

[.....]
INFO [main] 2009-10-09 11:23:37,320 CassandraDaemon.java (line 142)
Cassandra starting up...
INFO [PERIODIC-FLUSHER-POOL:1] 2009-10-09 11:24:40,239
ColumnFamilyStore.java (line 369) LocationInfo has reached its
threshold; switching in a fresh Memtable
INFO [PERIODIC-FLUSHER-POOL:1] 2009-10-09 11:24:40,239
ColumnFamilyStore.java (line 1178) Enqueuing flush of
Memtable(LocationInfo)@2116316013
INFO [MEMTABLE-FLUSHER-POOL:1] 2009-10-09 11:24:41,039 Memtable.java
(line 186) Flushing Memtable(LocationInfo)@2116316013
DEBUG [COMMIT-LOG-WRITER] 2009-10-09 11:24:45,191 CommitLog.java (line 
466) discard completed log segments for
CommitLogContext(file='/var/lib/cassandra/commitlog/ CommitLog-1255087417263.log', 
position=257), column family 0. CFIDs are system:
TableMetadata(LocationInfo: 0, HintsColumnFamily: 1, }), Fetcher:
TableMetadata(PageSentences: 2, Pages: 3, PageWords: 4, WordPages: 6,
SentencePages: 5, }), }
DEBUG [COMMIT-LOG-WRITER] 2009-10-09 11:24:45,243 CommitLog.java (line 
509) Marking replay position 257 on commit log
/var/lib/cassandra/commitlog/CommitLog-1255087417263.log
INFO [MEMTABLE-FLUSHER-POOL:1] 2009-10-09 11:24:45,243 Memtable.java
(line 220) Completed flushing
/mnt/cassandra/data/system/LocationInfo-19-Data.db
DEBUG [MINOR-COMPACTION-POOL:1] 2009-10-09 11:27:08,228
SSTableReader.java (line 58) index size for bloom filter calc for file 
: /mnt/cassandra/data/Fetcher/WordPages-347-Data.db : 256
DEBUG [MINOR-COMPACTION-POOL:1] 2009-10-09 11:27:08,228
SSTableReader.java (line 58) index size for bloom filter calc for file 
: /mnt/cassandra/data/Fetcher/WordPages-416-Data.db : 512
DEBUG [MINOR-COMPACTION-POOL:1] 2009-10-09 11:27:08,228
SSTableReader.java (line 58) index size for bloom filter calc for file 
: /mnt/cassandra/data/Fetcher/WordPages-486-Data.db : 768
DEBUG [MINOR-COMPACTION-POOL:1] 2009-10-09 11:27:08,228
SSTableReader.java (line 58) index size for bloom filter calc for file 
: /mnt/cassandra/data/Fetcher/WordPages-555-Data.db : 1024
DEBUG [MINOR-COMPACTION-POOL:1] 2009-10-09 11:27:08,228
ColumnFamilyStore.java (line 1048) Expected bloom filter size : 1024
DEBUG [Timer-0] 2009-10-09 11:28:39,859 LoadDisseminator.java (line
40) Disseminating load info ...
DEBUG [Timer-0] 2009-10-09 11:33:40,783 LoadDisseminator.java (line
40) Disseminating load info ...
DEBUG [Timer-0] 2009-10-09 11:38:40,956 LoadDisseminator.java (line
40) Disseminating load info ...
DEBUG [Timer-0] 2009-10-09 11:43:40,064 LoadDisseminator.java (line
40) Disseminating load info ...


If I try to insert anything, I get stuff like this:

ERROR [pool-1-thread-5324] 2009-10-09 10:12:36,574 StorageProxy.java
(line 179) error writing key md5
java.util.concurrent.TimeoutException: Operation timed out - received
only 0 responses from .
at
org.apache.cassandra.service.QuorumResponseHandler.get (QuorumResponseHandler.java:88) 

at
org.apache.cassandra.service.StorageProxy.insertBlocking (StorageProxy.java:164) 

at
org.apache.cassandra.service.CassandraServer.doInsert (CassandraServer.java:468) 

at
org.apache.cassandra.service.CassandraServer.insert (CassandraServer.java:421) 

at
org.apache.cassandra.service.Cassandra$Processor$insert.process (Cassandra.java:824) 

at
org.apache.cassandra.service.Cassandra$Processor.process (Cassandra.java:627) 

at
org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run (TThreadPoolServer.java:253) 

at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask (ThreadPoolExecutor.java:886) 

at
java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:908) 

at java.lang.Thread.run(Thread.java:619)


Any ideas?

Best regards
Dan



--
Eric Bowman
Boboco Ltd
[email protected]
http://www.boboco.ie/ebowman/pubkey.pgp
+35318394189/+353872801532

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