Package org.jgroups.protocols

Class BATCH

java.lang.Object
org.jgroups.stack.Protocol
org.jgroups.protocols.BATCH
All Implemented Interfaces:
Lifecycle
public class BATCH extends Protocol
Batches messages near the top of the stack. This reduces the work done on the IO thread and reduces overhead, greatly increasing throughput for smaller message sizes (< 1k in test configurations). Also reduces the amount of header data by having one header for each batch. Conceptually, down messages are buffered then put in a wrapper message, so lower protocols only interact with the wrapper. On the receiving end, the batch is unwrapped when it reaches this protocol and then forwarded to higher protocols as individual messages in a loop.
Since:
5.x

  • Field Details

    • flush_interval

      protected long flush_interval

    • max_batch_size

      public int max_batch_size

    • num_msgs_sent

      protected long num_msgs_sent

    • num_ebs_sent

      protected long num_ebs_sent

    • num_ebs_sent_due_to_full_queue

      protected long num_ebs_sent_due_to_full_queue

    • num_ebs_sent_due_to_max_number_of_msgs

      protected long num_ebs_sent_due_to_max_number_of_msgs

    • num_ebs_sent_due_to_timeout

      protected long num_ebs_sent_due_to_timeout

    • nullAddress

      protected final NullAddress nullAddress

    • timer

      protected TimeScheduler timer

    • running

      protected volatile boolean running

    • flush_task

      protected Future<?> flush_task

    • msgMap

      protected Map<Address,BATCH.Buffer> msgMap

  • Constructor Details

    • BATCH

      public BATCH()

  • Method Details

    • avgBatchSize

      public double avgBatchSize()

    • init

      public void init() throws Exception
      Description copied from class: Protocol
      Called after a protocol has been created and before the protocol is started. Attributes are already set. Other protocols are not yet connected and events cannot yet be sent.
      Specified by:
      init in interface Lifecycle
      Overrides:
      init in class Protocol
      Throws:
      Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the the channel constructor will throw an exception

    • resetStats

      public void resetStats()
      Overrides:
      resetStats in class Protocol

    • down

      public Object down(Event evt)
      Description copied from class: Protocol
      An event is to be sent down the stack. A protocol may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the protocol may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down().
      Overrides:
      down in class Protocol

    • up

      public Object up(Event evt)
      Description copied from class: Protocol
      An event was received from the protocol below. Usually the current protocol will want to examine the event type and - depending on its type - perform some computation (e.g. removing headers from a MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event). Finally, the event is either a) discarded, or b) an event is sent down the stack using down_prot.down() or c) the event (or another event) is sent up the stack using up_prot.up().
      Overrides:
      up in class Protocol

    • handleViewChange

      protected void handleViewChange(List<Address> mbrs)

    • down

      public Object down(Message msg)
      Description copied from class: Protocol
      A message is sent down the stack. Protocols may examine the message and do something (e.g. add a header) with it, before passing it down.
      Overrides:
      down in class Protocol

    • up

      public Object up(Message msg)
      Description copied from class: Protocol
      A single message was received. Protocols may examine the message and do something (e.g. add a header) with it before passing it up.
      Overrides:
      up in class Protocol

    • up

      public void up(MessageBatch batch)
      Description copied from class: Protocol
      Sends up a multiple messages in a MessageBatch. The sender of the batch is always the same, and so is the destination (null == multicast messages). Messages in a batch can be OOB messages, regular messages, or mixed messages, although the transport itself will create initial MessageBatches that contain only either OOB or regular messages.

      The default processing below sends messages up the stack individually, based on a matching criteria (calling Protocol.accept(Message)), and - if true - calls Protocol.up(org.jgroups.Event) for that message and removes the message. If the batch is not empty, it is passed up, or else it is dropped.

      Subclasses should check if there are any messages destined for them (e.g. using MessageBatch.iterator(Predicate)), then possibly remove and process them and finally pass the batch up to the next protocol. Protocols can also modify messages in place, e.g. ENCRYPT could decrypt all encrypted messages in the batch, not remove them, and pass the batch up when done.

      Overrides:
      up in class Protocol
      Parameters:
      batch - The message batch

    • start

      public void start() throws Exception
      Description copied from class: Protocol
      This method is called on a JChannel.connect(String); starts work. Protocols are connected ready to receive events. Will be called from bottom to top.
      Specified by:
      start in interface Lifecycle
      Overrides:
      start in class Protocol
      Throws:
      Exception - Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, so JChannel.connect(String) will throw an exception

    • stop

      public void stop()
      Description copied from class: Protocol
      Called on a JChannel.disconnect(); stops work (e.g. by closing multicast socket). Will be called from top to bottom.
      Specified by:
      stop in interface Lifecycle
      Overrides:
      stop in class Protocol

    • startFlushTask

      public void startFlushTask()

    • stopFlushTask

      public void stopFlushTask()

    • flush

      public void flush()