org.apache.flink.runtime.query.netty

Class KvStateServer

java.lang.Object

org.apache.flink.runtime.query.netty.KvStateServer

public class KvStateServer
extends Object

Netty-based server answering KvStateRequest messages.

Requests are handled by asynchronous query tasks (see KvStateServerHandler.AsyncKvStateQueryTask) that are executed by a separate query Thread pool. This pool is shared among all TCP connections.

The incoming pipeline looks as follows:

 Socket.read() -> LengthFieldBasedFrameDecoder -> KvStateServerHandler
 

Received binary messages are expected to contain a frame length field. Netty's LengthFieldBasedFrameDecoder is used to fully receive the frame before giving it to our KvStateServerHandler.

Connections are established and closed by the client. The server only closes the connection on a fatal failure that cannot be recovered. A server-side connection close is considered a failure by the client.

Constructor Summary

Constructors

Constructor and Description
KvStateServer(InetAddress bindAddress, int bindPort, int numEventLoopThreads, int numQueryThreads, KvStateRegistry kvStateRegistry, KvStateRequestStats stats) Creates the KvStateServer.

Method Summary

Methods

Modifier and Type	Method and Description
KvStateServerAddress	getAddress() Returns the address of this server.
void	shutDown() Shuts down the server and all related thread pools.
void	start() Starts the server by binding to the configured bind address (blocking).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

KvStateServer

public KvStateServer(InetAddress bindAddress,
             int bindPort,
             int numEventLoopThreads,
             int numQueryThreads,
             KvStateRegistry kvStateRegistry,
             KvStateRequestStats stats)

Creates the KvStateServer.

The server needs to be started via start() in order to bind to the configured bind address.

Parameters:

bindAddress - Address to bind to

bindPort - Port to bind to. Pick random port if 0.

numEventLoopThreads - Number of event loop threads

numQueryThreads - Number of query threads

kvStateRegistry - KvStateRegistry to query for KvState instances

stats - Statistics tracker

Method Detail

start

public void start()
           throws InterruptedException

Starts the server by binding to the configured bind address (blocking).

Throws:

InterruptedException - If interrupted during the bind operation

getAddress

public KvStateServerAddress getAddress()

Returns the address of this server.

Returns:

Server address

Throws:

IllegalStateException - If server has not been started yet

shutDown

public void shutDown()

Shuts down the server and all related thread pools.