[
https://issues.apache.org/jira/browse/CASSANDRA-9636?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14705098#comment-14705098
]
Chris Burroughs commented on CASSANDRA-9636:
--------------------------------------------
I'm a little confused after reading this ticket, is `select now() from
system.local;` a good query that should work or a bad one that needs a better
error message?
> Duplicate columns in selection causes AssertionError
> ----------------------------------------------------
>
> Key: CASSANDRA-9636
> URL: https://issues.apache.org/jira/browse/CASSANDRA-9636
> Project: Cassandra
> Issue Type: Bug
> Reporter: Sam Tunnicliffe
> Assignee: Sam Tunnicliffe
> Fix For: 2.2.0 rc2, 2.1.8, 2.0.17, 3.0 alpha 1
>
> Attachments: 9636-2.0.txt, 9636-2.1.txt, 9636-2.2.txt, 9636-trunk.txt
>
>
> Prior to CASSANDRA-9532, unaliased duplicate fields in a selection would be
> silently ignored. Now, they trigger a server side exception and an unfriendly
> error response, which we should clean up. Duplicate columns *with* aliases
> are not affected.
> {code}
> CREATE KEYSPACE ks WITH replication = {'class': 'SimpleStrategy',
> 'replication_factor': 1};
> CREATE TABLE ks.t1 (k int PRIMARY KEY, v int);
> INSERT INTO ks.t2 (k, v) VALUES (0, 0);
> SELECT k, v FROM ks.t2;
> SELECT k, v, v AS other_v FROM ks.t2;
> SELECT k, v, v FROM ks.t2;
> {code}
> The final statement results in this error response & server side stacktrace:
> {code}
> ServerError: <ErrorMessage code=0000 [Server error]
> message="java.lang.AssertionError">
> ERROR 13:01:30 Unexpected exception during request; channel = [id:
> 0x44d22e61, /127.0.0.1:39463 => /127.0.0.1:9042]
> java.lang.AssertionError: null
> at org.apache.cassandra.cql3.ResultSet.addRow(ResultSet.java:63)
> ~[main/:na]
> at
> org.apache.cassandra.cql3.statements.Selection$ResultSetBuilder.build(Selection.java:355)
> ~[main/:na]
> at
> org.apache.cassandra.cql3.statements.SelectStatement.process(SelectStatement.java:1226)
> ~[main/:na]
> at
> org.apache.cassandra.cql3.statements.SelectStatement.processResults(SelectStatement.java:299)
> ~[main/:na]
> at
> org.apache.cassandra.cql3.statements.SelectStatement.execute(SelectStatement.java:238)
> ~[main/:na]
> at
> org.apache.cassandra.cql3.statements.SelectStatement.execute(SelectStatement.java:67)
> ~[main/:na]
> at
> org.apache.cassandra.cql3.QueryProcessor.processStatement(QueryProcessor.java:238)
> ~[main/:na]
> at
> org.apache.cassandra.cql3.QueryProcessor.process(QueryProcessor.java:260)
> ~[main/:na]
> at
> org.apache.cassandra.transport.messages.QueryMessage.execute(QueryMessage.java:119)
> ~[main/:na]
> at
> org.apache.cassandra.transport.Message$Dispatcher.channelRead0(Message.java:439)
> [main/:na]
> at
> org.apache.cassandra.transport.Message$Dispatcher.channelRead0(Message.java:335)
> [main/:na]
> at
> io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
> [netty-all-4.0.23.Final.jar:4.0.23.Final]
> at
> io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333)
> [netty-all-4.0.23.Final.jar:4.0.23.Final]
> at
> io.netty.channel.AbstractChannelHandlerContext.access$700(AbstractChannelHandlerContext.java:32)
> [netty-all-4.0.23.Final.jar:4.0.23.Final]
> at
> io.netty.channel.AbstractChannelHandlerContext$8.run(AbstractChannelHandlerContext.java:324)
> [netty-all-4.0.23.Final.jar:4.0.23.Final]
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> [na:1.8.0_45]
> at
> org.apache.cassandra.concurrent.AbstractTracingAwareExecutorService$FutureTask.run(AbstractTracingAwareExecutorService.java:164)
> [main/:na]
> at org.apache.cassandra.concurrent.SEPWorker.run(SEPWorker.java:105)
> [main/:na]
> at java.lang.Thread.run(Thread.java:745) [na:1.8.0_45]
> {code}
> This issue also presents on the head of the 2.2 branch and on 2.0.16.
> However, the prior behaviour is different on both of those branches.
> In the 2.0 line prior to CASSANDRA-9532, duplicate columns would actually be
> included in the results, as opposed to being silently dropped as per 2.1.x
> In 2.2, the assertion error seen above precedes CASSANDRA-9532 and is also
> triggered for both aliased and unaliased duplicate columns.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
