Package org.jgroups.protocols

Class MERGE3

  • All Implemented Interfaces:
    Lifecycle
    public class MERGE3
extends Protocol
    Protocol to discover subgroups; e.g., existing due to a network partition (that healed). Example: group {p,q,r,s,t,u,v,w} is split into 3 subgroups {p,q}, {r,s,t,u} and {v,w}. This protocol will eventually send a MERGE event with the views of each subgroup up the stack: {p,r,v}.

    Works as follows (https://issues.redhat.com/browse/JGRP-1387): every member periodically broadcasts its address (UUID), logical name, physical address and ViewID information. Other members collect this information and see if the ViewIds are different (indication of different subpartitions). If they are, the member with the lowest address (first in the sorted list of collected addresses) sends a MERGE event up the stack, which will be handled by GMS. The others do nothing.

    The advantage compared to MERGE2 is that there are no merge collisions caused by multiple merges going on. Also, the INFO traffic is spread out over max_interval, and every member sends its physical address with INFO, so we don't need to fetch the physical address first.

    Since:
    3.1
    Author:
    Bela Ban, Nov 2011

    • Field Detail

      • min_interval

        protected long min_interval

      • max_interval

        protected long max_interval

      • max_participants_in_merge

        protected int max_participants_in_merge

      • check_interval

        protected long check_interval

      • view

        protected volatile View view

      • info_sender_future

        protected java.util.concurrent.Future<?> info_sender_future

      • view_consistency_checker

        protected java.util.concurrent.Future<?> view_consistency_checker

      • transport_supports_multicasting

        protected boolean transport_supports_multicasting

      • cluster_name

        protected java.lang.String cluster_name

      • discovery_rsp_cb

        protected final java.util.function.Consumer<PingData> discovery_rsp_cb

      • ASYNC_DISCOVERY_EVENT

        protected final Event ASYNC_DISCOVERY_EVENT

      • is_coord

        protected volatile boolean is_coord

      • num_merge_events

        protected int num_merge_events

    • Constructor Detail

      • MERGE3

        public MERGE3()

    • Method Detail

      • getViews

        public int getViews()

      • getNumMergeEvents

        public int getNumMergeEvents()

      • isViewConsistencyCheckerRunning

        public boolean isViewConsistencyCheckerRunning()

      • isMergeTaskRunning

        public boolean isMergeTaskRunning()

      • isInfoSenderRunning

        public boolean isInfoSenderRunning()

      • dumpViews

        public java.lang.String dumpViews()

      • clearViews

        public void clearViews()

      • sendInfo

        public void sendInfo()

      • checkInconsistencies

        public void checkInconsistencies()

      • init

        public void init()
          throws java.lang.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:
        java.lang.Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the the channel constructor will throw an exception

      • start

        public void start()
           throws java.lang.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:
        java.lang.Exception - Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, so JChannel.connect(String) will throw an exception

      • getMinInterval

        public long getMinInterval()

      • setMinInterval

        public MERGE3 setMinInterval​(long i)

      • getMaxInterval

        public long getMaxInterval()

      • setMaxInterval

        public MERGE3 setMaxInterval​(long val)

      • getCheckInterval

        public long getCheckInterval()

      • setCheckInterval

        public MERGE3 setCheckInterval​(long ci)

      • getMaxParticipantsInMerge

        public int getMaxParticipantsInMerge()

      • setMaxParticipantsInMerge

        public MERGE3 setMaxParticipantsInMerge​(int m)

      • isCoord

        public boolean isCoord()

      • computeCheckInterval

        protected long computeCheckInterval()

      • isMergeRunning

        protected boolean isMergeRunning()

      • startInfoSender

        protected void startInfoSender()

      • stopInfoSender

        protected void stopInfoSender()

      • startViewConsistencyChecker

        protected void startViewConsistencyChecker()

      • stopViewConsistencyChecker

        protected void stopViewConsistencyChecker()

      • down

        public java.lang.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 java.lang.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

      • detectDifferentViews

        public static java.util.List<View> detectDifferentViews​(java.util.Map<Address,​View> map)

      • readView

        protected View readView​(byte[] buffer,
                        int offset,
                        int length)

      • addInfo

        protected void addInfo​(Address sender,
                       ViewId view_id,
                       java.lang.String logical_name,
                       PhysicalAddress physical_addr)
        Adds received INFO to views hashmap

      • convertViews

        protected java.util.Map<ViewId,​java.util.Set<Address>> convertViews()

      • differentViewIds

        protected boolean differentViewIds()

      • sendInfoMessage

        protected void sendInfoMessage​(PingData data)