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From "Tyler Hobbs (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CASSANDRA-11570) Concurrent execution of prepared statement returns invalid JSON as result
Date Fri, 15 Apr 2016 16:24:25 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-11570?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Tyler Hobbs updated CASSANDRA-11570:
------------------------------------
    Status: Awaiting Feedback  (was: Open)

> Concurrent execution of prepared statement returns invalid JSON as result
> -------------------------------------------------------------------------
>
>                 Key: CASSANDRA-11570
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-11570
>             Project: Cassandra
>          Issue Type: Bug
>         Environment: Cassandra 3.2, C++ or C# driver
>            Reporter: Alexander Ryabets
>            Assignee: Tyler Hobbs
>         Attachments: CassandraPreparedStatementsTest.zip, broken_output.txt, test_neptunao.cql,
valid_output.txt
>
>
> When I use prepared statement for async execution of multiple statements I get JSON with
broken data. Keys got totally corrupted when values seems to be normal though.
> First I encoutered this issue when I were performing stress testing of our project using
custom script. We are using DataStax C++ driver and execute statements from different fibers.
> Then I was trying to isolate problem and wrote simple C# program which starts multiple
Tasks in a loop. Each task uses the once created prepared statement to read data from the
base. As you can see results are totally mess.
> I 've attached archive with console C# project (1 cs file) which just print resulting
JSON to user. 
> Here is the main part of C# code.
> {noformat}
> static void Main(string[] args)
> {
>   const int task_count = 300;
>   using(var cluster = Cluster.Builder().AddContactPoints(/*contact points here*/).Build())
>   {
>     using(var session = cluster.Connect())
>     {
>       var prepared = session.Prepare("select json * from test_neptunao.ubuntu where id=?");
>       var tasks = new Task[task_count];
>       for(int i = 0; i < task_count; i++)
>       {
>         tasks[i] = Query(prepared, session);
>       }
>       Task.WaitAll(tasks);
>     }
>   }
>   Console.ReadKey();
> }
> private static Task Query(PreparedStatement prepared, ISession session)
> {
>   string id = GetIdOfRandomRow();
>   var stmt = prepared.Bind(id);
>   stmt.SetConsistencyLevel(ConsistencyLevel.One);
>   return session.ExecuteAsync(stmt).ContinueWith(tr =>
>   {
>     foreach(var row in tr.Result)
>     {
>       var value = row.GetValue<string>(0);
>       //some kind of output
>     }
>   });
> }
> {noformat}
> I also attached cql script with test DB schema.
> {noformat}
> CREATE KEYSPACE IF NOT EXISTS test_neptunao
> WITH replication = {
> 	'class' : 'SimpleStrategy',
> 	'replication_factor' : 3
> };
> use test_neptunao;
> create table if not exists ubuntu (
> 	id timeuuid PRIMARY KEY,
> 	precise_pangolin text,
> 	trusty_tahr text,
> 	wily_werewolf text,	
> 	vivid_vervet text,
> 	saucy_salamander text,
> 	lucid_lynx text
> );
> {noformat}



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