/** * Invoked upon receiving a MERGE event from the MERGE layer. Starts the merge protocol. See * description of protocol in DESIGN. * * @param views A List of <em>different</em> views detected by the merge protocol */ public void merge(Map<Address, View> views) { if (isMergeInProgress()) { if (log.isTraceEnabled()) log.trace(gms.local_addr + ": merge is already running (merge_id=" + merge_id + ")"); return; } // we need the merge *coordinators* not merge participants because not everyone can lead a merge // ! Collection<Address> coords = Util.determineMergeCoords(views); Collection<Address> merge_participants = Util.determineMergeParticipants(views); Membership tmp = new Membership(coords); // establish a deterministic order, so that coords can elect leader tmp.sort(); Address merge_leader = tmp.elementAt(0); if (log.isDebugEnabled()) log.debug("determining merge leader from " + merge_participants); if (merge_leader.equals(gms.local_addr)) { if (log.isDebugEnabled()) log.debug( "I (" + gms.local_addr + ") will be the leader. Starting the merge task for " + merge_participants); merge_task.start(views); } else { if (log.isDebugEnabled()) log.debug( "I (" + gms.local_addr + ") am not the merge leader, " + "waiting for merge leader (" + merge_leader + ") to initiate merge"); } }
public static void testDetermineMergeParticipantsAndMergeCoords4() { Address a = Util.createRandomAddress(), b = Util.createRandomAddress(), c = Util.createRandomAddress(), d = Util.createRandomAddress(); org.jgroups.util.UUID.add(a, "A"); org.jgroups.util.UUID.add(b, "B"); org.jgroups.util.UUID.add(c, "C"); org.jgroups.util.UUID.add(d, "D"); View v1 = View.create(a, 1, a, b); View v2 = View.create(c, 1, c, d); Map<Address, View> map = new HashMap<>(); map.put(a, v1); map.put(b, v1); map.put(d, v2); StringBuilder sb = new StringBuilder("map:\n"); for (Map.Entry<Address, View> entry : map.entrySet()) sb.append(entry.getKey() + ": " + entry.getValue() + "\n"); System.out.println(sb); Collection<Address> merge_participants = Util.determineMergeParticipants(map); System.out.println("merge_participants = " + merge_participants); assert merge_participants.size() == 3; assert merge_participants.contains(a) && merge_participants.contains(c) && merge_participants.contains(d); Collection<Address> merge_coords = Util.determineMergeCoords(map); System.out.println("merge_coords = " + merge_coords); assert merge_coords.size() == 2; assert merge_coords.contains(a) && merge_coords.contains(c); }
/** * @param views Guaranteed to be non-null and to have >= 2 members, or else this thread would * not be started */ public synchronized void start(Map<Address, View> views) { if (thread == null || thread.isAlive()) { this.coords.clear(); // now remove all members which don't have us in their view, so RPCs won't block (e.g. // FLUSH) // https://jira.jboss.org/browse/JGRP-1061 sanitizeViews(views); // Add all different coordinators of the views into the hashmap and sets their members: Collection<Address> coordinators = Util.determineMergeCoords(views); for (Address coord : coordinators) { View view = views.get(coord); if (view != null) this.coords.put(coord, new ArrayList<Address>(view.getMembers())); } // For the merge participants which are not coordinator, we simply add them, and the // associated // membership list consists only of themselves Collection<Address> merge_participants = Util.determineMergeParticipants(views); merge_participants.removeAll(coordinators); for (Address merge_participant : merge_participants) { Collection<Address> tmp = new ArrayList<Address>(); tmp.add(merge_participant); coords.putIfAbsent(merge_participant, tmp); } thread = gms.getThreadFactory().newThread(this, "MergeTask"); thread.setDaemon(true); thread.start(); } }