/// <summary> 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.
/// </summary>
/// <param name="v">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.
/// </param>
internal virtual MergeData consolidateMergeData(System.Collections.ArrayList v)
{
MergeData ret = null;
MergeData tmp_data;
long logical_time = 0; // for new_vid
ViewId new_vid, tmp_vid;
MergeView new_view;
View tmp_view;
Membership new_mbrs = new Membership();
int num_mbrs = 0;
Digest new_digest = null;
Address new_coord;
System.Collections.ArrayList subgroups = System.Collections.ArrayList.Synchronized(new System.Collections.ArrayList(11));
// contains a list of Views, each View is a subgroup
for (int i = 0; i < v.Count; i++)
{
tmp_data = (MergeData)v[i];
gms.Stack.NCacheLog.Debug("merge data is " + tmp_data);
tmp_view = tmp_data.View;
if (tmp_view != null)
{
tmp_vid = tmp_view.Vid;
if (tmp_vid != null)
{
// compute the new view id (max of all vids +1)
logical_time = System.Math.Max(logical_time, tmp_vid.Id);
}
}
// merge all membership lists into one (prevent duplicates)
new_mbrs.add(tmp_view.Members);
subgroups.Add(tmp_view.Clone());
}
// the new coordinator is the first member of the consolidated & sorted membership list
new_mbrs.sort();
num_mbrs = new_mbrs.size();
new_coord = num_mbrs > 0 ? (Address)new_mbrs.elementAt(0) : null;
if (new_coord == null)
{
gms.Stack.NCacheLog.Error("CoordGmsImpl.consolodateMergeData", "new_coord is null.");
return null;
}
// should be the highest view ID seen up to now plus 1
new_vid = new ViewId(new_coord, logical_time + 1);
// determine the new view
new_view = new MergeView(new_vid, new_mbrs.Members, subgroups);
gms.Stack.NCacheLog.Debug("new merged view will be " + new_view);
// determine the new digest
new_digest = consolidateDigests(v, num_mbrs);
if (new_digest == null)
{
gms.Stack.NCacheLog.Error("CoordGmsImpl.consolidateMergeData", "digest could not be consolidated.");
return null;
}
gms.Stack.NCacheLog.Debug("consolidated digest=" + new_digest);
ret = new MergeData(gms.local_addr, new_view, new_digest);
return ret;
}
/// <summary> Invoked upon receiving a MERGE event from the MERGE layer. Starts the merge protocol.
/// See description of protocol in DESIGN.
/// </summary>
/// <param name="other_coords">A list of coordinators (including myself) found by MERGE protocol
/// </param>
public override void merge(System.Collections.ArrayList other_coords)
{
Membership tmp;
Address leader = null;
if (merging)
{
gms.Stack.NCacheLog.Warn("CoordGmsImpl.merge", "merge already in progress, discarded MERGE event");
return;
}
if (other_coords == null)
{
gms.Stack.NCacheLog.Warn("CoordGmsImpl.merge", "list of other coordinators is null. Will not start merge.");
return;
}
if (other_coords.Count <= 1)
{
gms.Stack.NCacheLog.Error("CoordGmsImpl.merge", "number of coordinators found is " + other_coords.Count + "; will not perform merge");
return;
}
/* Establish deterministic order, so that coords can elect leader */
tmp = new Membership(other_coords);
tmp.sort();
leader = (Address)tmp.elementAt(0);
gms.Stack.NCacheLog.Debug("coordinators in merge protocol are: " + tmp);
if (leader.Equals(gms.local_addr))
{
gms.Stack.NCacheLog.Debug("I (" + leader + ") will be the leader. Starting the merge task");
startMergeTask(other_coords);
}
}
/// <summary>
/// Sets the membership to the specified membership
/// </summary>
/// <param name="m">New membership</param>
public void set(Membership m)
{
clear();
if (m != null)
{
add(m.Members);
}
}
/// <summary>
/// Clones the membership
/// </summary>
/// <returns>A clone of the membership</returns>
public Object Clone()
{
Membership m;
m = new Membership();
m.setMembers((ArrayList)members.Clone());
return(m);
}
/// <summary> Sets the new view and sends a VIEW_CHANGE event up and down the stack.</summary>
public virtual void installView(View new_view)
{
Stack.NCacheLog.CriticalInfo("GMS.InstallView", "Installing new View " + local_addr.ToString() + " --> " + new_view);
Address coord = null;
try
{
//Lest inform coordinator about view receiption
SendViewAcknowledgment(new_view.Coordinator);
int rc;
ViewId vid = new_view.Vid;
System.Collections.ArrayList mbrs = new_view.Members;
impl.UniqueId = new_view.BridgeSourceCacheId;
_uniqueID = new_view.BridgeSourceCacheId;
if (Stack.NCacheLog.IsInfoEnabled) Stack.NCacheLog.Info("[local_addr=" + local_addr + "] view is " + new_view);
// Discards view with id lower than our own. Will be installed without check if first view
if (view_id != null)
{
rc = vid.CompareTo(view_id);
if (rc <= 0)
{
Stack.NCacheLog.Error("[" + local_addr + "] received view <= current view;" + " discarding it (current vid: " + view_id + ", new vid: " + vid + ')');
Event viewEvt = new Event(Event.VIEW_CHANGE_OK, null, Priority.Critical);
passDown(viewEvt);
return;
}
Address currentCoodinator = determineCoordinator();
Address newCoordinator = new_view.Coordinator;
Address sender = vid.CoordAddress; // creater of the view
if (!currentCoodinator.Equals(newCoordinator) && !newCoordinator.Equals(local_addr) && !sender.Equals(currentCoodinator))
{
Stack.NCacheLog.CriticalInfo("GMS.InstallView", "Force Join Cluster");
if (!new_view.ForceInstall)
{
if (!VerifySuspect(currentCoodinator))
{
Stack.NCacheLog.Error("GMS.installView", "rejecting the view from " + newCoordinator + " as my own coordinator[" + currentCoodinator + "] is not down");
Event viewEvt = new Event(Event.VIEW_CHANGE_OK, null, Priority.Critical);
passDown(viewEvt);
//we should inform the coordinator of this view that i can't be the member
//of your view as my own coordinator is alive.
Message msg = new Message(new_view.Coordinator, null, new byte[0]);
msg.putHeader(HeaderType.GMS, new GMS.HDR(GMS.HDR.VIEW_REJECTED, local_addr));
passDown(new Event(Event.MSG, msg, Priority.Critical));
return;
}
}
}
}
ltime = System.Math.Max(vid.Id, ltime); // compute Lamport logical time
/* 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 (checkSelfInclusion(mbrs) == false)
{
Stack.NCacheLog.Error("GMS.InstallView", "CheckSelfInclusion() failed, " + local_addr + " is not a member of view " + new_view + "; discarding view");
// only shun if this member was previously part of the group. avoids problem where multiple
// members (e.g. X,Y,Z) join {A,B} concurrently, X is joined first, and Y and Z get view
// {A,B,X}, which would cause Y and Z to be shunned as they are not part of the membership
// bela Nov 20 2003
if (shun && local_addr != null && prev_members.contains(local_addr))
{
Stack.NCacheLog.CriticalInfo("I (" + local_addr + ") am being shunned, will leave and " + "rejoin group (prev_members are " + prev_members + ')');
passUp(new Event(Event.EXIT));
}
return;
}
lock (members)
{
//@UH Members are same as in the previous view. No need to apply view
if (view_id != null)
{
Membership newMembers = new Membership(mbrs);
if (members.Equals(newMembers) && vid.CoordAddress.Equals(view_id.CoordAddress))
{
Stack.NCacheLog.Error("GMS.InstallView", "[" + local_addr + "] received view has the same members as current view;" + " discarding it (current vid: " + view_id + ", new vid: " + vid + ')');
Event viewEvt = new Event(Event.VIEW_CHANGE_OK, null, Priority.Critical);
//#usama@15-4-2013 joining, leaving and tmp_members are needed to be synchronized even if view is same
Global.ICollectionSupport.RemoveAll(joining, mbrs); // remove all members in mbrs from joining
// remove all elements from 'leaving' that are not in 'mbrs'
Global.ICollectionSupport.RetainAll(leaving, 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
passDown(viewEvt);
return;
}
}
//=========================================
//
Stack.NCacheLog.CriticalInfo("GMS.InstallView", "Installing view in gms");
if (Stack.NCacheLog.IsInfoEnabled) Stack.NCacheLog.Info("GMS.InstallView " + new_view.ToString() + "\\n" + "seq tble : " + new_view.SequencerTbl.Count);
this._subGroupMbrsMap = new_view.SequencerTbl.Clone() as System.Collections.Hashtable;
this._mbrSubGroupMap = new_view.MbrsSubgroupMap.Clone() as System.Collections.Hashtable;
//=========================================
// serialize access to views
// assign new_view to view_id
view_id = vid.Copy();
Stack.NCacheLog.CriticalInfo("GMS.InstallView", "=== View ID = " + view_id.ToString());
// Set the membership. Take into account joining members
if (mbrs != null && mbrs.Count > 0)
{
for (int i = 0; i < members.size(); i++)
{
Address mbr = members.elementAt(i);
if (!mbrs.Contains(mbr))
RemoveGmsId(mbr);
}
Hashtable gmsIds = new_view.GmsIds;
if (gmsIds != null)
{
IDictionaryEnumerator ide = gmsIds.GetEnumerator();
while (ide.MoveNext())
{
if(Stack.NCacheLog.IsInfoEnabled) Stack.NCacheLog.Info("GMS.InstallView", "mbr = " + ide.Key + " ; gms_id = " + ide.Value);
AddGmsId((Address)ide.Key, (string)ide.Value);
}
}
for (int i = 0; i < mbrs.Count; i++)
{
Stack.NCacheLog.CriticalInfo("GMS.InstallView", "Members.set = " + mbrs[i] != null ? mbrs[i].ToString() : null);
}
members.set(mbrs);
tmp_members.set(members);
Global.ICollectionSupport.RemoveAll(joining, mbrs); // remove all members in mbrs from joining
// remove all elements from 'leaving' that are not in 'mbrs'
Global.ICollectionSupport.RetainAll(leaving, 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 (System.Collections.IEnumerator it = mbrs.GetEnumerator(); it.MoveNext(); )
{
Address addr = (Address)it.Current;
if (!prev_members.contains(addr))
prev_members.add(addr);
}
}
// Send VIEW_CHANGE event up and down the stack:
if (Stack.NCacheLog.IsInfoEnabled) Stack.NCacheLog.Info("GMS.installView", "broadcasting view change within stack");
coord = determineCoordinator();
// changed on suggestion by yaronr and Nicolas Piedeloupe
if (coord != null && coord.Equals(local_addr) && !haveCoordinatorRole())
{
becomeCoordinator();
}
else
{
if (haveCoordinatorRole() && !local_addr.Equals(coord))
becomeParticipant();
}
if (string.IsNullOrEmpty(new_view.BridgeSourceCacheId))
new_view.BridgeSourceCacheId = impl.UniqueId;
MarkStateTransferInProcess();
Event view_event = new Event(Event.VIEW_CHANGE, new_view.Clone(), Priority.Critical);
passDown(view_event); // needed e.g. by failure detector or UDP
}
}
finally
{
}
}
