Jason Reber created CASSANDRA-5382:
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Summary: ConcurrentModificantionException on server when multiple
read CQL3 read requests recieved on single column family simultaneously.
Key: CASSANDRA-5382
URL: https://issues.apache.org/jira/browse/CASSANDRA-5382
Project: Cassandra
Issue Type: Bug
Affects Versions: 1.2.3
Environment: SLES, Sun JDK 1.6.0_43
Reporter: Jason Reber
Priority: Minor
The exception below is thrown on the server when two reads are performed at the
exact same time on the same column family. This causes the query to fail.
The problem appears to be caused by the 'name' list in
org.apache.cassandra.cql3.ResultSet$Metadata. The reference is passed in to the
constructor and iterated without copying and without a synch block. When two of
these ResultSet instances are created from the same metadata list at the same
time, a ConcurrentModificationException is thrown.
The error:
ERROR [Thrift:860] 2013-03-25 09:27:39,467 CustomTThreadPoolServer.java (line
217) Error occurred during processing of message.
java.util.ConcurrentModificationException
at
java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
at java.util.AbstractList$Itr.next(AbstractList.java:343)
at
org.apache.cassandra.cql3.ResultSet$Metadata.allInSameCF(ResultSet.java:237)
at
org.apache.cassandra.cql3.ResultSet$Metadata.<init>(ResultSet.java:219)
at org.apache.cassandra.cql3.ResultSet.<init>(ResultSet.java:47)
at
org.apache.cassandra.cql3.statements.Selection$ResultSetBuilder.<init>(Selection.java:239)
at
org.apache.cassandra.cql3.statements.Selection$ResultSetBuilder.<init>(Selection.java:221)
at
org.apache.cassandra.cql3.statements.Selection.resultSetBuilder(Selection.java:211)
at
org.apache.cassandra.cql3.statements.SelectStatement.process(SelectStatement.java:655)
at
org.apache.cassandra.cql3.statements.SelectStatement.processResults(SelectStatement.java:147)
at
org.apache.cassandra.cql3.statements.SelectStatement.execute(SelectStatement.java:136)
at
org.apache.cassandra.cql3.statements.SelectStatement.execute(SelectStatement.java:62)
at
org.apache.cassandra.cql3.QueryProcessor.processStatement(QueryProcessor.java:132)
at
org.apache.cassandra.cql3.QueryProcessor.processPrepared(QueryProcessor.java:254)
at
org.apache.cassandra.thrift.CassandraServer.execute_prepared_cql3_query(CassandraServer.java:1851)
at
org.apache.cassandra.thrift.Cassandra$Processor$execute_prepared_cql3_query.getResult(Cassandra.java:4166)
at
org.apache.cassandra.thrift.Cassandra$Processor$execute_prepared_cql3_query.getResult(Cassandra.java:4154)
at org.apache.thrift.ProcessFunction.process(ProcessFunction.java:32)
at org.apache.thrift.TBaseProcessor.process(TBaseProcessor.java:34)
at
org.apache.cassandra.thrift.CustomTThreadPoolServer$WorkerProcess.run(CustomTThreadPoolServer.java:199)
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:662)
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