protected void _handleMergeRequest(
Address sender, MergeId merge_id, Collection<? extends Address> mbrs) throws Exception {
boolean success = matchMergeId(merge_id) || setMergeId(null, merge_id);
if (!success)
throw new Exception(
"merge " + this.merge_id + " is already in progress, received merge-id=" + merge_id);
/* Clears the view handler queue and discards all JOIN/LEAVE/MERGE requests until after the MERGE */
// gms.getViewHandler().suspend();
if (log.isTraceEnabled())
log.trace(
gms.local_addr
+ ": got merge request from "
+ sender
+ ", merge_id="
+ merge_id
+ ", mbrs="
+ mbrs);
// merge the membership of the current view with mbrs
List<Address> members = new LinkedList<Address>();
if (mbrs
!= null) { // didn't use a set because we didn't want to change the membership order at this
// time (although not incorrect)
for (Address mbr : mbrs) {
if (!members.contains(mbr)) members.add(mbr);
}
}
ViewId tmp_vid = gms.getViewId();
if (tmp_vid != null) tmp_vid = tmp_vid.copy();
if (tmp_vid == null) throw new Exception("view ID is null; cannot return merge response");
View view = new View(tmp_vid, new ArrayList<Address>(members));
// [JGRP-524] - FLUSH and merge: flush doesn't wrap entire merge process
// [JGRP-770] - Concurrent startup of many channels doesn't stabilize
// [JGRP-700] - FLUSH: flushing should span merge
/*if flush is in stack, let this coordinator flush its cluster island */
if (gms.flushProtocolInStack && !gms.startFlush(view)) throw new Exception("flush failed");
// we still need to fetch digests from all members, and not just return our own digest
// (https://issues.jboss.org/browse/JGRP-948)
Digest digest = fetchDigestsFromAllMembersInSubPartition(members, merge_id);
if (digest == null || digest.size() == 0)
throw new Exception(
"failed fetching digests from subpartition members; dropping merge response");
sendMergeResponse(sender, view, digest, merge_id);
}
/**
* Merge all MergeData. All MergeData elements should be disjunct (both views and digests).
* However, this method is prepared to resolve duplicate entries (for the same member).
* Resolution strategy for views is to merge only 1 of the duplicate members. Resolution
* strategy for digests is to take the higher seqnos for duplicate digests.
*
* <p>After merging all members into a Membership and subsequent sorting, the first member of
* the sorted membership will be the new coordinator. This method has a lock on merge_rsps.
*
* @param merge_rsps A list of MergeData items. Elements with merge_rejected=true were removed
* before. Is guaranteed not to be null and to contain at least 1 member.
*/
private MergeData consolidateMergeData(Vector<MergeData> merge_rsps) {
long logical_time = 0; // for new_vid
Membership new_mbrs = new Membership();
Vector<View> subgroups =
new Vector<View>(11); // contains a list of Views, each View is a subgroup
for (MergeData tmp_data : merge_rsps) {
View tmp_view = tmp_data.getView();
if (tmp_view != null) {
ViewId tmp_vid = tmp_view.getVid();
if (tmp_vid != null) {
// compute the new view id (max of all vids +1)
logical_time = Math.max(logical_time, tmp_vid.getId());
}
// merge all membership lists into one (prevent duplicates)
new_mbrs.add(tmp_view.getMembers());
subgroups.addElement((View) tmp_view.clone());
}
}
// the new coordinator is the first member of the consolidated & sorted membership list
new_mbrs.sort();
Address new_coord = new_mbrs.size() > 0 ? new_mbrs.elementAt(0) : null;
if (new_coord == null) {
if (log.isErrorEnabled()) log.error("new_coord == null");
return null;
}
// should be the highest view ID seen up to now plus 1
ViewId new_vid = new ViewId(new_coord, logical_time + 1);
// determine the new view
MergeView new_view = new MergeView(new_vid, new_mbrs.getMembers(), subgroups);
// determine the new digest
Digest new_digest = consolidateDigests(merge_rsps, new_mbrs.size());
if (new_digest == null) {
if (log.isErrorEnabled())
log.error("Merge leader " + gms.local_addr + ": could not consolidate digest for merge");
return null;
}
if (log.isDebugEnabled())
log.debug(
"Merge leader "
+ gms.local_addr
+ ": consolidated view="
+ new_view
+ "\nconsolidated digest="
+ new_digest);
return new MergeData(gms.local_addr, new_view, new_digest);
}
/**
* Merge all MergeData. All MergeData elements should be disjunct (both views and digests).
* However, this method is prepared to resolve duplicate entries (for the same member).
* Resolution strategy for views is to merge only 1 of the duplicate members. Resolution
* strategy for digests is to take the higher seqnos for duplicate digests.
*
* <p>After merging all members into a Membership and subsequent sorting, the first member of
* the sorted membership will be the new coordinator. This method has a lock on merge_rsps.
*
* @param merge_rsps A list of MergeData items. Elements with merge_rejected=true were removed
* before. Is guaranteed not to be null and to contain at least 1 member.
*/
private MergeData consolidateMergeData(List<MergeData> merge_rsps) {
long logical_time = 0; // for new_vid
List<View> subgroups =
new ArrayList<View>(11); // contains a list of Views, each View is a subgroup
Collection<Collection<Address>> sub_mbrships = new ArrayList<Collection<Address>>();
for (MergeData tmp_data : merge_rsps) {
View tmp_view = tmp_data.getView();
if (tmp_view != null) {
ViewId tmp_vid = tmp_view.getVid();
if (tmp_vid != null) {
// compute the new view id (max of all vids +1)
logical_time = Math.max(logical_time, tmp_vid.getId());
}
// merge all membership lists into one (prevent duplicates)
sub_mbrships.add(new ArrayList<Address>(tmp_view.getMembers()));
subgroups.add(tmp_view.copy());
}
}
// determine the new digest
Digest new_digest = consolidateDigests(merge_rsps, merge_rsps.size());
if (new_digest == null) return null;
// remove all members from the new member list that are not in the digest
Collection<Address> digest_mbrs = new_digest.getMembers();
for (Collection<Address> coll : sub_mbrships) coll.retainAll(digest_mbrs);
List<Address> merged_mbrs = gms.computeNewMembership(sub_mbrships);
// the new coordinator is the first member of the consolidated & sorted membership list
Address new_coord = merged_mbrs.isEmpty() ? null : merged_mbrs.get(0);
if (new_coord == null) return null;
// should be the highest view ID seen up to now plus 1
ViewId new_vid = new ViewId(new_coord, logical_time + 1);
// determine the new view
MergeView new_view = new MergeView(new_vid, merged_mbrs, subgroups);
if (log.isTraceEnabled())
log.trace(
gms.local_addr
+ ": consolidated view="
+ new_view
+ "\nconsolidated digest="
+ new_digest);
return new MergeData(gms.local_addr, new_view, new_digest);
}
/**
* Computes the next view. Returns a copy that has <code>old_mbrs</code> and <code>suspected_mbrs
* </code> removed and <code>new_mbrs</code> added.
*/
public View getNextView(
Collection<Address> new_mbrs,
Collection<Address> old_mbrs,
Collection<Address> suspected_mbrs) {
synchronized (members) {
ViewId view_id = view != null ? view.getViewId() : null;
if (view_id == null) {
log.error("view_id is null");
return null; // this should *never* happen !
}
long vid = Math.max(view_id.getId(), ltime) + 1;
ltime = vid;
Membership tmp_mbrs = tmp_members.copy(); // always operate on the temporary membership
tmp_mbrs.remove(suspected_mbrs);
tmp_mbrs.remove(old_mbrs);
tmp_mbrs.add(new_mbrs);
List<Address> mbrs = tmp_mbrs.getMembers();
Address new_coord = local_addr;
if (!mbrs.isEmpty()) new_coord = mbrs.get(0);
View v = new View(new_coord, vid, mbrs);
// Update membership (see DESIGN for explanation):
tmp_members.set(mbrs);
// Update joining list (see DESIGN for explanation)
if (new_mbrs != null) {
for (Address tmp_mbr : new_mbrs) {
if (!joining.contains(tmp_mbr)) joining.add(tmp_mbr);
}
}
// Update leaving list (see DESIGN for explanations)
if (old_mbrs != null) {
for (Address addr : old_mbrs) {
if (!leaving.contains(addr)) leaving.add(addr);
}
}
if (suspected_mbrs != null) {
for (Address addr : suspected_mbrs) {
if (!leaving.contains(addr)) leaving.add(addr);
}
}
return v;
}
}
/**
* An event was received from the layer below. Usually the current layer 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 <code>
* PassDown</code> or c) the event (or another event) is sent up the stack using <code>PassUp
* </code>.
*
* <p>For the PING protocol, the Up operation does the following things. 1. If the event is a
* Event.MSG then PING will inspect the message header. If the header is null, PING simply passes
* up the event If the header is PingHeader.GET_MBRS_REQ then the PING protocol will PassDown a
* PingRequest message If the header is PingHeader.GET_MBRS_RSP we will add the message to the
* initial members vector and wake up any waiting threads. 2. If the event is Event.SET_LOCAL_ADDR
* we will simple set the local address of this protocol 3. For all other messages we simple pass
* it up to the protocol above
*
* @param evt - the event that has been sent from the layer below
*/
@SuppressWarnings("unchecked")
public Object up(Event evt) {
switch (evt.getType()) {
case Event.MSG:
Message msg = (Message) evt.getArg();
PingHeader hdr = (PingHeader) msg.getHeader(this.id);
if (hdr == null) return up_prot.up(evt);
PingData data = hdr.data;
Address logical_addr = data != null ? data.getAddress() : null;
if (is_leaving) return null; // prevents merging back a leaving member
// (https://issues.jboss.org/browse/JGRP-1336)
switch (hdr.type) {
case PingHeader.GET_MBRS_REQ: // return Rsp(local_addr, coord)
if (group_addr == null || hdr.cluster_name == null) {
if (log.isWarnEnabled())
log.warn(
"group_addr ("
+ group_addr
+ ") or cluster_name of header ("
+ hdr.cluster_name
+ ") is null; passing up discovery request from "
+ msg.getSrc()
+ ", but this should not"
+ " be the case");
} else {
if (!group_addr.equals(hdr.cluster_name)) {
if (log.isWarnEnabled())
log.warn(
"discarding discovery request for cluster '"
+ hdr.cluster_name
+ "' from "
+ msg.getSrc()
+ "; our cluster name is '"
+ group_addr
+ "'. "
+ "Please separate your clusters cleanly.");
return null;
}
}
// add physical address and logical name of the discovery sender (if available) to the
// cache
if (data != null) {
if (logical_addr == null) logical_addr = msg.getSrc();
Collection<PhysicalAddress> physical_addrs = data.getPhysicalAddrs();
PhysicalAddress physical_addr =
physical_addrs != null && !physical_addrs.isEmpty()
? physical_addrs.iterator().next()
: null;
if (logical_addr != null && physical_addr != null)
down(
new Event(
Event.SET_PHYSICAL_ADDRESS,
new Tuple<Address, PhysicalAddress>(logical_addr, physical_addr)));
if (logical_addr != null && data.getLogicalName() != null)
UUID.add(logical_addr, data.getLogicalName());
discoveryRequestReceived(msg.getSrc(), data.getLogicalName(), physical_addrs);
synchronized (ping_responses) {
for (Responses response : ping_responses) {
response.addResponse(data, false);
}
}
}
if (hdr.view_id != null) {
// If the discovery request is merge-triggered, and the ViewId shipped with it
// is the same as ours, we don't respond (JGRP-1315).
ViewId my_view_id = view != null ? view.getViewId() : null;
if (my_view_id != null && my_view_id.equals(hdr.view_id)) return null;
boolean send_discovery_rsp =
force_sending_discovery_rsps
|| is_coord
|| current_coord == null
|| current_coord.equals(msg.getSrc());
if (!send_discovery_rsp) {
if (log.isTraceEnabled())
log.trace(
local_addr
+ ": suppressing merge response as I'm not a coordinator and the "
+ "discovery request was not sent by a coordinator");
return null;
}
}
if (isMergeRunning()) {
if (log.isTraceEnabled())
log.trace(
local_addr + ": suppressing merge response as a merge is already in progress");
return null;
}
List<PhysicalAddress> physical_addrs =
hdr.view_id != null
? null
: Arrays.asList(
(PhysicalAddress) down(new Event(Event.GET_PHYSICAL_ADDRESS, local_addr)));
sendDiscoveryResponse(
local_addr,
physical_addrs,
is_server,
hdr.view_id != null,
UUID.get(local_addr),
msg.getSrc());
return null;
case PingHeader.GET_MBRS_RSP: // add response to vector and notify waiting thread
// add physical address (if available) to transport's cache
if (data != null) {
Address response_sender = msg.getSrc();
if (logical_addr == null) logical_addr = msg.getSrc();
Collection<PhysicalAddress> addrs = data.getPhysicalAddrs();
PhysicalAddress physical_addr =
addrs != null && !addrs.isEmpty() ? addrs.iterator().next() : null;
if (logical_addr != null && physical_addr != null)
down(
new Event(
Event.SET_PHYSICAL_ADDRESS,
new Tuple<Address, PhysicalAddress>(logical_addr, physical_addr)));
if (logical_addr != null && data.getLogicalName() != null)
UUID.add(logical_addr, data.getLogicalName());
if (log.isTraceEnabled())
log.trace(
local_addr + ": received GET_MBRS_RSP from " + response_sender + ": " + data);
boolean overwrite = logical_addr != null && logical_addr.equals(response_sender);
synchronized (ping_responses) {
for (Responses response : ping_responses) {
response.addResponse(data, overwrite);
}
}
}
return null;
default:
if (log.isWarnEnabled())
log.warn("got PING header with unknown type (" + hdr.type + ')');
return null;
}
case Event.GET_PHYSICAL_ADDRESS:
try {
sendDiscoveryRequest(group_addr, null, null);
} catch (InterruptedIOException ie) {
if (log.isWarnEnabled()) {
log.warn("Discovery request for cluster " + group_addr + " interrupted");
}
Thread.currentThread().interrupt();
} catch (Exception ex) {
if (log.isErrorEnabled()) log.error("failed sending discovery request", ex);
}
return null;
case Event.FIND_INITIAL_MBRS: // sent by transport
return findInitialMembers(null);
}
return up_prot.up(evt);
}
/**
* Sets the new view and sends a VIEW_CHANGE event up and down the stack. If the view is a
* MergeView (subclass of View), then digest will be non-null and has to be set before installing
* the view.
*/
public void installView(View new_view, Digest digest) {
ViewId vid = new_view.getVid();
List<Address> mbrs = new_view.getMembers();
ltime =
Math.max(
vid.getId(),
ltime); // compute the logical time, regardless of whether the view is accepted
// Discards view with id lower than or equal to our own. Will be installed without check if it
// is the first view
if (view != null) {
ViewId view_id = view.getViewId();
int rc = vid.compareToIDs(view_id);
if (rc <= 0) {
if (log.isWarnEnabled()
&& rc < 0
&& log_view_warnings) { // only scream if view is smaller, silently discard same views
log.warn(
local_addr
+ ": received view < current view;"
+ " discarding it (current vid: "
+ view_id
+ ", new vid: "
+ vid
+ ')');
}
return;
}
}
/* Check for self-inclusion: if I'm not part of the new membership, I just discard it.
This ensures that messages sent in view V1 are only received by members of V1 */
if (!mbrs.contains(local_addr)) {
if (log.isWarnEnabled() && log_view_warnings)
log.warn(local_addr + ": not member of view " + new_view.getViewId() + "; discarding it");
return;
}
if (digest != null) {
if (new_view instanceof MergeView) mergeDigest(digest);
else setDigest(digest);
}
if (log.isDebugEnabled()) log.debug(local_addr + ": installing view " + new_view);
Event view_event;
synchronized (members) {
view = new View(new_view.getVid(), new_view.getMembers());
view_event = new Event(Event.VIEW_CHANGE, new_view);
// Set the membership. Take into account joining members
if (!mbrs.isEmpty()) {
members.set(mbrs);
tmp_members.set(members);
joining.removeAll(mbrs); // remove all members in mbrs from joining
// remove all elements from 'leaving' that are not in 'mbrs'
leaving.retainAll(mbrs);
tmp_members.add(joining); // add members that haven't yet shown up in the membership
tmp_members.remove(
leaving); // remove members that haven't yet been removed from the membership
// add to prev_members
for (Address addr : mbrs) {
if (!prev_members.contains(addr)) prev_members.add(addr);
}
}
Address coord = determineCoordinator();
if (coord != null && coord.equals(local_addr) && !haveCoordinatorRole()) {
becomeCoordinator();
} else {
if (haveCoordinatorRole() && !local_addr.equals(coord)) {
becomeParticipant();
merge_ack_collector.reset(null); // we don't need this one anymore
}
}
}
// - Changed order of passing view up and down (http://jira.jboss.com/jira/browse/JGRP-347)
// - Changed it back (bela Sept 4 2007): http://jira.jboss.com/jira/browse/JGRP-564
// - Moved sending up view_event out of the synchronized block (bela Nov 2011)
down_prot.down(view_event); // needed e.g. by failure detector or UDP
up_prot.up(view_event);
List<Address> tmp_mbrs = new_view.getMembers();
ack_collector.retainAll(tmp_mbrs);
merge_ack_collector.retainAll(tmp_mbrs);
if (new_view instanceof MergeView) merger.forceCancelMerge();
if (stats) {
num_views++;
prev_views.add(new Tuple<View, Long>(new_view, System.currentTimeMillis()));
}
}