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Posted to commits@cassandra.apache.org by "basanth gowda (JIRA)" <ji...@apache.org> on 2012/08/29 15:45:07 UTC

[jira] [Commented] (CASSANDRA-4532) NPE when trying to select a slice from a composite table

    [ https://issues.apache.org/jira/browse/CASSANDRA-4532?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13444059#comment-13444059 ] 

basanth gowda commented on CASSANDRA-4532:
------------------------------------------

I was trying to get a slice range, like you could do in thrift.

table defn :

create tables schedules(status ascii, timecreated bigint, key ascii, nil ascii, PRIMARY KEY(status,timecreated,key));

for the same time there can be a lot of entries.

Lets suppose there are 50 entries that match where timecreated is < Ln

1st query : select * from schedules where timecreated <= <Ln> limit 10;


2nd Query : select * from schedules where timecreated>=L10 AND key=K10 and timecreated<Ln.

In CQL terms this is a wrong query I know, basically not sure how to represent Between in CQL


In Hector I would do, get slice range limiting 10 first time, 

for the next query (until no more are returned) I would use the time returned by last query and key returned by last query as the start range. This is in production and works perfectly fine
                
> NPE when trying to select a slice from a composite table
> --------------------------------------------------------
>
>                 Key: CASSANDRA-4532
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4532
>             Project: Cassandra
>          Issue Type: Bug
>          Components: API, Core
>    Affects Versions: 1.1.3
>         Environment: Cassandra 1.1.3 (2 nodes) on a single host - mac osx
>            Reporter: basanth gowda
>            Priority: Minor
>              Labels: Slice, cql, cql3
>
> I posted this question on StackOverflow, because i need a solution. 
> Created a table with :
> {noformat}
> create table compositetest(m_id ascii,i_id int,l_id ascii,body ascii, PRIMARY KEY(m_id,i_id,l_id));
> {noformat}
> wanted to slice the results returned, so did something like below, not sure if its the right way. The first one returns data perfectly as expected, second one to get the next 3 columns closes the transport of my cqlsh
> {noformat}
> cqlsh:testkeyspace1> select * from compositetest where i_id<=3 limit 3;
>  m_id | i_id | l_id | body
> ------+------+------+------
>    m1 |    1 |   l1 |   b1
>    m1 |    2 |   l2 |   b2
>    m2 |    1 |   l1 |   b1
> cqlsh:testkeyspace1> Was trying to write something for slice range.
> TSocket read 0 bytes
> {noformat}
> Is there a way to achieve what I am doing here, it would be good if some meaning ful error is sent back, instead of cqlsh closing the transport.
> On the server side I see the following error.
> {noformat}
> ERROR [Thrift:3] 2012-08-12 15:15:24,414 CustomTThreadPoolServer.java (line 204) Error occurred during processing of message.
> java.lang.NullPointerException
> 	at org.apache.cassandra.cql3.statements.SelectStatement$Restriction.setBound(SelectStatement.java:1277)
> 	at org.apache.cassandra.cql3.statements.SelectStatement$RawStatement.updateRestriction(SelectStatement.java:1151)
> 	at org.apache.cassandra.cql3.statements.SelectStatement$RawStatement.prepare(SelectStatement.java:1001)
> 	at org.apache.cassandra.cql3.QueryProcessor.getStatement(QueryProcessor.java:215)
> 	at org.apache.cassandra.cql3.QueryProcessor.process(QueryProcessor.java:121)
> 	at org.apache.cassandra.thrift.CassandraServer.execute_cql_query(CassandraServer.java:1237)
> 	at org.apache.cassandra.thrift.Cassandra$Processor$execute_cql_query.getResult(Cassandra.java:3542)
> 	at org.apache.cassandra.thrift.Cassandra$Processor$execute_cql_query.getResult(Cassandra.java:3530)
> 	at org.apache.thrift.ProcessFunction.process(ProcessFunction.java:32)
> 	at org.apache.thrift.TBaseProcessor.process(TBaseProcessor.java:34)
> 	at org.apache.cassandra.thrift.CustomTThreadPoolServer$WorkerProcess.run(CustomTThreadPoolServer.java:186)
> 	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:680)
> {noformat}
> With ThriftClient I get :
> {noformat}
> org.apache.thrift.transport.TTransportException
> 	at org.apache.thrift.transport.TIOStreamTransport.read(TIOStreamTransport.java:132)
> 	at org.apache.thrift.transport.TTransport.readAll(TTransport.java:84)
> 	at org.apache.thrift.transport.TFramedTransport.readFrame(TFramedTransport.java:129)
> 	at org.apache.thrift.transport.TFramedTransport.read(TFramedTransport.java:101)
> 	at org.apache.thrift.transport.TTransport.readAll(TTransport.java:84)
> 	at org.apache.thrift.protocol.TBinaryProtocol.readAll(TBinaryProtocol.java:378)
> 	at org.apache.thrift.protocol.TBinaryProtocol.readI32(TBinaryProtocol.java:297)
> 	at org.apache.thrift.protocol.TBinaryProtocol.readMessageBegin(TBinaryProtocol.java:204)
> 	at org.apache.thrift.TServiceClient.receiveBase(TServiceClient.java:69)
> 	at org.apache.cassandra.thrift.Cassandra$Client.recv_execute_cql_query(Cassandra.java:1402)
> 	at org.apache.cassandra.thrift.Cassandra$Client.execute_cql_query(Cassandra.java:1388)
> {noformat}

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