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https://issues.apache.org/jira/browse/CASSANDRA-3861?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13204223#comment-13204223
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Jonathan Ellis commented on CASSANDRA-3861:
-------------------------------------------
Man, performance vs helping people do the Right Thing, that's a tough call. :)
Is allocating a 10K list array that much of a performance hit? My intuition is
that it's negligible compared to actually performing the query.
> get_indexed_slices throws OOM Error when is called with too big
> indexClause.count
> ---------------------------------------------------------------------------------
>
> Key: CASSANDRA-3861
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3861
> Project: Cassandra
> Issue Type: Bug
> Components: API, Core
> Affects Versions: 1.0.7
> Reporter: Vladimir Tsanev
> Assignee: Sylvain Lebresne
> Fix For: 1.0.8
>
> Attachments: 3861.patch
>
>
> I tried to call get_index_slices with Integer.MAX_VALUE as IndexClause.count.
> Unfortunately the node died with OOM. In the log there si following error:
> ERROR [Thrift:4] 2012-02-06 17:43:39,224 Cassandra.java (line 3252) Internal
> error processing get_indexed_slices
> java.lang.OutOfMemoryError: Java heap space
> at java.util.ArrayList.<init>(ArrayList.java:112)
> at
> org.apache.cassandra.service.StorageProxy.scan(StorageProxy.java:1067)
> at
> org.apache.cassandra.thrift.CassandraServer.get_indexed_slices(CassandraServer.java:746)
> at
> org.apache.cassandra.thrift.Cassandra$Processor$get_indexed_slices.process(Cassandra.java:3244)
> at
> org.apache.cassandra.thrift.Cassandra$Processor.process(Cassandra.java:2889)
> at
> org.apache.cassandra.thrift.CustomTThreadPoolServer$WorkerProcess.run(CustomTThreadPoolServer.java:187)
> 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:662)
> Is it necessary to allocate all the memory in advance. I only have 3 KEYS
> that match my caluse. I do not known the exact number but in general I am
> sure that they wil fit in the memory.
> I can/will implement some calls with paging, but wanted to test and I am not
> happy with the fact the node disconnected.
> I wonder why ArrayList is used here?
> I think the result is never accessed by index (but only iterated) and the
> subList for non RandomAccess Lists (for example LinkedList) will do the same
> job if you are not using other operations than iteration.
> Is this related to the problem described in CASSANDRA-691.
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