Question

我使用CQL用cassandra准备了一些表。实际上，我尝试对我的数据应用聚合查询（sum，avg等）。所以，我在java中使用了presto-cassandra。我已按如下方式配置presto：

Config.properties：

coordinator=true
node-scheduler.include-coordinator=true
http-server.http.port=8080
task.max-memory=1GB
discovery-server.enabled=true
discovery.uri= `http://localhost:8080`

JVM.properties：

-server
-Xmx16G
-XX:+UseConcMarkSweepGC
-XX:+ExplicitGCInvokesConcurrent
-XX:+CMSClassUnloadingEnabled
-XX:+AggressiveOpts
-XX:+HeapDumpOnOutOfMemoryError
-XX:OnOutOfMemoryError=kill -9 %p
-XX:PermSize=150M
-XX:MaxPermSize=150M
-XX:ReservedCodeCacheSize=150M
-Xbootclasspath/p:C:/Presto/lib/floatingdecimal-0.1.jar

log.properties：

com.facebook.presto=INFO

node.properties：

node.environment=production
node.id=ffffffff-ffff-ffff-ffff-ffffffffffff
node.data-dir=C:/Presto/data

cassandra.properties：

connector.name=cassandra
cassandra.contact-points=localhost
cassandra.native-protocol-port=9142
cassandra.thrift-port=9160

然后，我一直在尝试连接到presto并通过jdbc运行一些查询，但我一直在收到错误。代码是：

public static void connect() throws ClassNotFoundException, SQLException{
    Class.forName("com.facebook.presto.jdbc.PrestoDriver");
    PrestoConnection connection = (PrestoConnection) DriverManager.getConnection("jdbc:presto://localhost:8080/cassandra/premierkeys", "test","");
    PrestoStatement statement = (PrestoStatement) connection.createStatement();
    ResultSet rs = statement.executeQuery("select * from client");
    while(rs.next()) {
        System.out.println(rs.getString(1));
    }       
}
public static void main(String[] args) throws ClassNotFoundException, SQLException {
    // TODO Auto-generated method stub
    connect();
}

此外，maven依赖关系如下所示：

<dependencies>
    <dependency>
        <groupId>com.facebook.presto</groupId>
        <artifactId>presto-cassandra</artifactId>
        <version>0.72</version>
        <type>zip</type>
    </dependency>
    <dependency>
        <groupId>com.facebook.presto</groupId>
        <artifactId>presto-jdbc</artifactId>
        <version>0.72</version>
    </dependency>
</dependencies>`

但是当我运行这段代码时，我得到了：

***juil. 02, 2014 11:32:57 AM com.facebook.presto.jdbc.internal.jetty.util.log.JavaUtilLog info
INFOS: Logging initialized @122ms
Exception in thread "main" java.sql.SQLException: Error executing query
    at com.facebook.presto.jdbc.PrestoStatement.executeQuery(PrestoStatement.java:54)
    at tester_cass.connect(tester_cass.java:19)
    at tester_cass.main(tester_cass.java:26)
Caused by: java.lang.IllegalStateException: Response does not contain a JSON value
    at com.facebook.presto.jdbc.internal.airlift.http.client.FullJsonResponseHandler$JsonResponse.getValue(FullJsonResponseHandler.java:148)
    at com.facebook.presto.jdbc.internal.client.StatementClient.<init>(StatementClient.java:82)
    at com.facebook.presto.jdbc.QueryExecutor.startQuery(QueryExecutor.java:60)
    at com.facebook.presto.jdbc.PrestoConnection.startQuery(PrestoConnection.java:541)
    at com.facebook.presto.jdbc.PrestoStatement.executeQuery(PrestoStatement.java:49)
    ... 2***

有什么问题？

Answer 1

隔离问题：

尝试通过Presto CLI
从http://<your-presto-coordinator>:8080/

来自cassandra连接的java.sql.SQLException和使用presto查询

1 个答案: