[DRILL-2444] JDBC creates non-daemon threads that outlive user's code

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 0.9.0
• Component/s: Client - JDBC
• Assignee: Rahul Kumar Challapalli
• Reporter: Rahul Kumar Challapalli
• Created: 12/Mar/15 20:26
• Updated: 04/May/15 23:46
• Resolved: 07/Apr/15 17:25

Description

I used the below maven dependency for the project :

<dependency>
    <groupId>org.apache.drill.exec</groupId>
    <artifactId>drill-jdbc-all</artifactId>
    <version>0.8.0-SNAPSHOT</version>
    <type>pom</type>
  </dependency>

When I run the below class through eclipse, I see debug messages from the JDBC code even after my man method finishes executing its last statement.

public class Dummy {

	static final String JDBC_DRIVER = "org.apache.drill.jdbc.Driver";  
	static final String DB_URL = "jdbc:drill:schema=dfs.drillTestDirViews;zk=x.x.x.x:5181/drill-build/cluster-drillbits";
	static Connection conn;
	
	public static void main(String[] args) throws Exception {
        Class.forName(JDBC_DRIVER);
	    System.out.println("Connecting to database...");
	    conn = DriverManager.getConnection(DB_URL);
	    conn.close();
	    System.out.println("End Of Main");
	}
}

Partial output from the console :

13:22:47.785 [Client-1] DEBUG io.netty.util.Recycler - -Dio.netty.recycler.maxCapacity.default: 262144
End Of Main
13:22:55.992 [main-SendThread(10.10.100.190:5181)] DEBUG org.apache.zookeeper.ClientCnxn - Got ping response for sessionid: 0x14a9c96266185ab after 0ms
13:23:09.338 [main-SendThread(10.10.100.190:5181)] DEBUG org.apache.zookeeper.ClientCnxn - Got ping response for sessionid: 0x14a9c96266185ab after 1ms

Even if I do not call close on the connection object, the JVM should exit when user code finishes execution.

Let me know if you have any questions

Issue Links

• is related to: DRILL-1735 JDBC driver's close() leaks resources in local mode