package org.jgroups.protocols.pbcast;
import org.jgroups.Address;
import org.jgroups.Event;
import org.jgroups.Message;
import org.jgroups.View;
import org.jgroups.annotations.*;
import org.jgroups.conf.PropertyConverters;
import org.jgroups.protocols.TP;
import org.jgroups.stack.*;
import org.jgroups.util.*;
import java.util.*;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
* Negative AcKnowledgement layer (NAKs). Messages are assigned a monotonically
* increasing sequence number (seqno). Receivers deliver messages ordered
* according to seqno and request retransmission of missing messages.<br/>
* Retransmit requests are usually sent to the original sender of a message, but
* this can be changed by xmit_from_random_member (send to random member) or
* use_mcast_xmit_req (send to everyone). Responses can also be sent to everyone
* instead of the requester by setting use_mcast_xmit to true.
*
* @author Bela Ban
*/
@MBean(description="Reliable transmission multipoint FIFO protocol")
public class NAKACK extends Protocol implements Retransmitter.RetransmitCommand, DiagnosticsHandler.ProbeHandler {
private static final int NUM_REBROADCAST_MSGS=3;
/* ----------------------------------------------------- Properties --------------------- ------------------------------------ */
@Property(name="retransmit_timeout", converter=PropertyConverters.IntegerArray.class, description="Timeout before requesting retransmissions")
private int[] retransmit_timeouts= { 600, 1200, 2400, 4800 }; // time(s) to wait before requesting retransmission
@Property(description="Max number of messages to be removed from a NakReceiverWindow. This property might " +
"get removed anytime, so don't use it !")
private int max_msg_batch_size=100;
/**
* Retransmit messages using multicast rather than unicast. This has the advantage that, if many receivers
* lost a message, the sender only retransmits once
*/
@Property(description="Retransmit retransmit responses (messages) using multicast rather than unicast")
private boolean use_mcast_xmit=true;
/**
* Use a multicast to request retransmission of missing messages. This may
* be costly as every member in the cluster will send a response
*/
@Property(description="Use a multicast to request retransmission of missing messages")
private boolean use_mcast_xmit_req=false;
@Property(description="Number of milliseconds to delay the sending of an XMIT request. We pick a random number " +
"in the range [1 .. xmit_req_stagger_timeout] and add this to the scheduling time of an XMIT request. " +
"When use_mcast_xmit is enabled, if a number of members drop messages from the same member, then chances are that, " +
"if staggering is enabled, somebody else already sent the XMIT request (via mcast) and we can cancel the XMIT " +
"request once we receive the missing messages. For unicast XMIT responses (use_mcast_xmit=false), we still have " +
"an advantage by not overwhelming the receiver with XMIT requests, all at the same time. 0 disabless staggering.")
protected long xmit_stagger_timeout=200;
/**
* Ask a random member for retransmission of a missing message. If set to
* true, discard_delivered_msgs will be set to false
*/
@Property(description="Ask a random member for retransmission of a missing message. Default is false")
private boolean xmit_from_random_member=false;
/**
* The first value (in milliseconds) to use in the exponential backoff
* retransmission mechanism. Only enabled if the value is > 0
*/
@Property(description="The first value (in milliseconds) to use in the exponential backoff. Enabled if greater than 0")
private int exponential_backoff=300;
@Property(description="Whether to use the old retransmitter which retransmits individual messages or the new one " +
"which uses ranges of retransmitted messages. Default is true. Note that this property will be removed in 3.0; " +
"it is only used to switch back to the old (and proven) retransmitter mechanism if issues occur")
private boolean use_range_based_retransmitter=true;
/**
* Messages that have been received in order are sent up the stack (=
* delivered to the application). Delivered messages are removed from
* NakReceiverWindow.xmit_table and moved to
* NakReceiverWindow.delivered_msgs, where they are later garbage collected
* (by STABLE). Since we do retransmits only from sent messages, never
* received or delivered messages, we can turn the moving to delivered_msgs
* off, so we don't keep the message around, and don't need to wait for
* garbage collection to remove them.
*/
@Property(description="Should messages delivered to application be discarded")
private boolean discard_delivered_msgs=true;
@Property(description="Timeout to rebroadcast messages. Default is 2000 msec")
private long max_rebroadcast_timeout=2000;
/** When not finding a message on an XMIT request, include the last N stability messages in the error message */
@Property(description="Should stability history be printed if we fail in retransmission. Default is false")
protected boolean print_stability_history_on_failed_xmit=false;
/** If true, logs messages discarded because received from other members */
@Property(description="discards warnings about promiscuous traffic")
private boolean log_discard_msgs=true;
@Property(description="If true, trashes warnings about retransmission messages not found in the xmit_table (used for testing)")
private boolean log_not_found_msgs=true;
@Property(description="Number of rows of the matrix in the retransmission table (only for experts)",writable=false)
int xmit_table_num_rows=5;
@Property(description="Number of elements of a row of the matrix in the retransmission table (only for experts). " +
"The capacity of the matrix is xmit_table_num_rows * xmit_table_msgs_per_row",writable=false)
int xmit_table_msgs_per_row=10000;
@Property(description="Resize factor of the matrix in the retransmission table (only for experts)",writable=false)
double xmit_table_resize_factor=1.2;
@Property(description="Number of milliseconds after which the matrix in the retransmission table " +
"is compacted (only for experts)",writable=false)
long xmit_table_max_compaction_time=10 * 60 * 1000;
@Property(description="Size of the queue to hold messages received after creating the channel, but before being " +
"connected (is_server=false). After becoming the server, the messages in the queue are fed into up() and the " +
"queue is cleared. The motivation is to avoid retransmissions (see https://issues.jboss.org/browse/JGRP-1509 " +
"for details). 0 disables the queue.")
protected int become_server_queue_size=50;
@Property(description="Time during which identical warnings about messages from a non member will be suppressed. " +
"0 disables this (every warning will be logged). Setting the log level to ERROR also disables this.")
protected long suppress_time_non_member_warnings=60000;
/* -------------------------------------------------- JMX ---------------------------------------------------------- */
@ManagedAttribute(description="Number of retransmit requests received")
private final AtomicLong xmit_reqs_received=new AtomicLong(0);
@ManagedAttribute(description="Number of retransmit requests sent")
private final AtomicLong xmit_reqs_sent=new AtomicLong(0);
@ManagedAttribute(description="Number of retransmit responses received")
private final AtomicLong xmit_rsps_received=new AtomicLong(0);
@ManagedAttribute(description="Number of retransmit responses sent")
private final AtomicLong xmit_rsps_sent=new AtomicLong(0);
@ManagedAttribute(description="Number of messages sent")
protected int num_messages_sent=0;
@ManagedAttribute(description="Number of messages received")
protected int num_messages_received=0;
@ManagedAttribute(description="Number of messages from non-members")
public int getNonMemberMessages() {
return suppress_log_non_member != null? suppress_log_non_member.getCache().size() : 0;
}
@ManagedOperation(description="Clears the cache for messages from non-members")
public void clearNonMemberCache() {
if(suppress_log_non_member != null)
suppress_log_non_member.getCache().clear();
}
/* ------------------------------------------------- Fields ------------------------------------------------------------------------- */
private volatile boolean is_server=false;
private Address local_addr=null;
private final List<Address> members=new CopyOnWriteArrayList<Address>();
private View view;
private final AtomicLong seqno=new AtomicLong(0); // current message sequence number (starts with 1)
/** Map to store sent and received messages (keyed by sender) */
private final ConcurrentMap<Address,NakReceiverWindow> xmit_table=Util.createConcurrentMap();
private volatile boolean leaving=false;
private volatile boolean running=false;
private TimeScheduler timer=null;
private final Lock rebroadcast_lock=new ReentrantLock();
private final Condition rebroadcast_done=rebroadcast_lock.newCondition();
// set during processing of a rebroadcast event
private volatile boolean rebroadcasting=false;
private final Lock rebroadcast_digest_lock=new ReentrantLock();
@GuardedBy("rebroadcast_digest_lock")
private Digest rebroadcast_digest=null;
/** Keeps the last 10 stability messages */
protected final BoundedList<String> stability_msgs=new BoundedList<String>(10);
/** Keeps a bounded list of the last N digest sets */
protected final BoundedList<String> digest_history=new BoundedList<String>(10);
protected BoundedList<Message> become_server_queue;
/** Log to suppress identical warnings for messages from non-members */
protected SuppressLog<Address> suppress_log_non_member;
public long getXmitRequestsReceived() {return xmit_reqs_received.get();}
public long getXmitRequestsSent() {return xmit_reqs_sent.get();}
public long getXmitResponsesReceived() {return xmit_rsps_received.get();}
public long getXmitResponsesSent() {return xmit_rsps_sent.get();}
@ManagedAttribute(description="Total number of missing messages")
public int getPendingXmitRequests() {
int num=0;
for(NakReceiverWindow win: xmit_table.values()) {
num+=win.getPendingXmits();
}
return num;
}
@ManagedAttribute
public int getXmitTableSize() {
int num=0;
for(NakReceiverWindow win: xmit_table.values()) {
num+=win.size();
}
return num;
}
@ManagedAttribute
public int getXmitTableMissingMessages() {
int num=0;
for(NakReceiverWindow win: xmit_table.values()) {
num+=win.getMissingMessages();
}
return num;
}
@ManagedAttribute(description="Returns the number of bytes of all messages in all NakReceiverWindows. To compute " +
"the size, Message.getLength() is used")
public long getSizeOfAllMessages() {
long retval=0;
for(NakReceiverWindow win: xmit_table.values())
retval+=win.sizeOfAllMessages(false);
return retval;
}
@ManagedAttribute(description="Returns the number of bytes of all messages in all NakReceiverWindows. To compute " +
"the size, Message.size() is used")
public long getSizeOfAllMessagesInclHeaders() {
long retval=0;
for(NakReceiverWindow win: xmit_table.values())
retval+=win.sizeOfAllMessages(true);
return retval;
}
@ManagedAttribute
public long getCurrentSeqno() {return seqno.get();}
@ManagedOperation
public String printRetransmitStats() {
StringBuilder sb=new StringBuilder();
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet())
sb.append(entry.getKey()).append(": ").append(entry.getValue().printRetransmitStats()).append("\n");
return sb.toString();
}
/**
* Please don't use this method; it is only provided for unit testing !
* @param mbr
* @return
*/
public NakReceiverWindow getWindow(Address mbr) {
return xmit_table.get(mbr);
}
/**
* Only used for unit tests, don't use !
* @param timer
*/
public void setTimer(TimeScheduler timer) {
this.timer=timer;
}
public void resetStats() {
num_messages_sent=num_messages_received=0;
xmit_reqs_received.set(0);
xmit_reqs_sent.set(0);
xmit_rsps_received.set(0);
xmit_rsps_sent.set(0);
stability_msgs.clear();
digest_history.clear();
}
public void init() throws Exception {
if(xmit_from_random_member) {
if(discard_delivered_msgs) {
discard_delivered_msgs=false;
log.debug("xmit_from_random_member set to true: changed discard_delivered_msgs to false");
}
}
TP transport=getTransport();
if(transport != null) {
transport.registerProbeHandler(this);
if(!transport.supportsMulticasting()) {
if(use_mcast_xmit) {
log.warn("use_mcast_xmit should not be used because the transport (" + transport.getName() +
") does not support IP multicasting; setting use_mcast_xmit to false");
use_mcast_xmit=false;
}
if(use_mcast_xmit_req) {
log.warn("use_mcast_xmit_req should not be used because the transport (" + transport.getName() +
") does not support IP multicasting; setting use_mcast_xmit_req to false");
use_mcast_xmit_req=false;
}
}
}
if(become_server_queue_size > 0)
become_server_queue=new BoundedList<Message>(become_server_queue_size);
if(suppress_time_non_member_warnings > 0)
suppress_log_non_member=new SuppressLog<Address>(log, "MsgDroppedNak", "SuppressMsg");
}
public boolean isUseMcastXmit() {
return use_mcast_xmit;
}
public void setUseMcastXmit(boolean use_mcast_xmit) {
this.use_mcast_xmit=use_mcast_xmit;
}
public boolean isXmitFromRandomMember() {
return xmit_from_random_member;
}
public void setXmitFromRandomMember(boolean xmit_from_random_member) {
this.xmit_from_random_member=xmit_from_random_member;
}
public boolean isDiscardDeliveredMsgs() {
return discard_delivered_msgs;
}
public void setDiscardDeliveredMsgs(boolean discard_delivered_msgs) {
this.discard_delivered_msgs=discard_delivered_msgs;
}
public void setLogDiscardMessages(boolean flag) {
log_discard_msgs=flag;
}
public void setLogDiscardMsgs(boolean flag) {
setLogDiscardMessages(flag);
}
public boolean getLogDiscardMessages() {
return log_discard_msgs;
}
public Map<String,Object> dumpStats() {
Map<String,Object> retval=super.dumpStats();
retval.put("msgs", printMessages());
return retval;
}
public String printStats() {
StringBuilder sb=new StringBuilder();
sb.append("\nStability messages received\n");
sb.append(printStabilityMessages()).append("\n");
return sb.toString();
}
@ManagedOperation(description="TODO")
public String printStabilityMessages() {
StringBuilder sb=new StringBuilder();
sb.append(Util.printListWithDelimiter(stability_msgs, "\n"));
return sb.toString();
}
public String printStabilityHistory() {
StringBuilder sb=new StringBuilder();
int i=1;
for(String digest: stability_msgs) {
sb.append(i++).append(": ").append(digest).append("\n");
}
return sb.toString();
}
@ManagedOperation(description="Keeps information about the last N times a digest was set or merged")
public String printDigestHistory() {
StringBuilder sb=new StringBuilder(local_addr + ":\n");
for(String tmp: digest_history)
sb.append(tmp).append("\n");
return sb.toString();
}
@ManagedOperation(description="TODO")
public String printLossRates() {
StringBuilder sb=new StringBuilder();
NakReceiverWindow win;
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
win=entry.getValue();
sb.append(entry.getKey()).append(": ").append(win.printLossRate()).append("\n");
}
return sb.toString();
}
@ManagedOperation(description="Returns the sizes of all NakReceiverWindow.RetransmitTables")
public String printRetransmitTableSizes() {
StringBuilder sb=new StringBuilder();
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
NakReceiverWindow win=entry.getValue();
sb.append(entry.getKey() + ": ").append(win.getRetransmitTableSize())
.append(", offset=").append(win.getRetransmitTableOffset())
.append(" (capacity=" + win.getRetransmitTableCapacity())
.append(", fill factor=" + win.getRetransmitTableFillFactor() + "%)\n");
}
return sb.toString();
}
@ManagedOperation(description="Compacts the retransmission tables")
public void compact() {
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
NakReceiverWindow win=entry.getValue();
win.compact();
}
}
public List<Integer> providedUpServices() {
return Arrays.asList(Event.GET_DIGEST, Event.SET_DIGEST, Event.OVERWRITE_DIGEST, Event.MERGE_DIGEST);
}
public void start() throws Exception {
if((timer=getTransport().getTimer()) == null)
throw new Exception("timer is null");
running=true;
leaving=false;
}
public void stop() {
running=false;
is_server=false;
if(become_server_queue != null)
become_server_queue.clear();
reset(); // clears sent_msgs and destroys all NakReceiverWindows
}
/**
* <b>Callback</b>. Called by superclass when event may be handled.<p> <b>Do not use <code>down_prot.down()</code> in this
* method as the event is passed down by default by the superclass after this method returns !</b>
*/
public Object down(Event evt) {
switch(evt.getType()) {
case Event.MSG:
Message msg=(Message)evt.getArg();
Address dest=msg.getDest();
if(dest != null || msg.isFlagSet(Message.NO_RELIABILITY))
break; // unicast address: not null and not mcast, pass down unchanged
send(evt, msg);
return null; // don't pass down the stack
case Event.STABLE: // generated by STABLE layer. Delete stable messages passed in arg
stable((Digest)evt.getArg());
return null; // do not pass down further (Bela Aug 7 2001)
case Event.GET_DIGEST:
return getDigest((Address)evt.getArg());
case Event.SET_DIGEST:
setDigest((Digest)evt.getArg());
return null;
case Event.OVERWRITE_DIGEST:
overwriteDigest((Digest)evt.getArg());
return null;
case Event.MERGE_DIGEST:
mergeDigest((Digest)evt.getArg());
return null;
case Event.TMP_VIEW:
View tmp_view=(View)evt.getArg();
List<Address> mbrs=tmp_view.getMembers();
members.clear();
members.addAll(mbrs);
break;
case Event.VIEW_CHANGE:
tmp_view=(View)evt.getArg();
mbrs=tmp_view.getMembers();
members.clear();
members.addAll(mbrs);
view=tmp_view;
adjustReceivers(members);
is_server=true; // check vids from now on
if(suppress_log_non_member != null)
suppress_log_non_member.removeExpired(suppress_time_non_member_warnings);
break;
case Event.BECOME_SERVER:
is_server=true;
flushBecomeServerQueue();
break;
case Event.SET_LOCAL_ADDRESS:
local_addr=(Address)evt.getArg();
break;
case Event.DISCONNECT:
leaving=true;
reset();
break;
case Event.REBROADCAST:
rebroadcasting=true;
rebroadcast_digest=(Digest)evt.getArg();
try {
rebroadcastMessages();
}
finally {
rebroadcasting=false;
rebroadcast_digest_lock.lock();
try {
rebroadcast_digest=null;
}
finally {
rebroadcast_digest_lock.unlock();
}
}
return null;
}
return down_prot.down(evt);
}
/**
* <b>Callback</b>. Called by superclass when event may be handled.<p> <b>Do not use <code>PassUp</code> in this
* method as the event is passed up by default by the superclass after this method returns !</b>
*/
public Object up(Event evt) {
switch(evt.getType()) {
case Event.MSG:
Message msg=(Message)evt.getArg();
if(msg.isFlagSet(Message.Flag.NO_RELIABILITY))
break;
NakAckHeader hdr=(NakAckHeader)msg.getHeader(this.id);
if(hdr == null)
break; // pass up (e.g. unicast msg)
if(!is_server) { // discard messages while not yet server (i.e., until JOIN has returned)
if(become_server_queue != null) {
become_server_queue.add(msg);
if(log.isTraceEnabled())
log.trace(local_addr + ": message " + msg.getSrc() + "::" + hdr.seqno + " was added to queue (not yet server)");
}
else {
if(log.isTraceEnabled())
log.trace(local_addr + ": message " + msg.getSrc() + "::" + hdr.seqno + " was discarded (not yet server)");
}
return null;
}
// Changed by bela Jan 29 2003: we must not remove the header, otherwise further xmit requests will fail !
//hdr=(NakAckHeader)msg.removeHeader(getName());
switch(hdr.type) {
case NakAckHeader.MSG:
handleMessage(msg, hdr);
return null; // transmitter passes message up for us !
case NakAckHeader.XMIT_REQ:
if(hdr.range == null) {
if(log.isErrorEnabled()) {
log.error("XMIT_REQ: range of xmit msg is null; discarding request from " + msg.getSrc());
}
return null;
}
handleXmitReq(msg.getSrc(), hdr.range.low, hdr.range.high, hdr.sender);
return null;
case NakAckHeader.XMIT_RSP:
handleXmitRsp(msg, hdr);
return null;
default:
if(log.isErrorEnabled()) {
log.error("NakAck header type " + hdr.type + " not known !");
}
return null;
}
case Event.STABLE: // generated by STABLE layer. Delete stable messages passed in arg
stable((Digest)evt.getArg());
return null; // do not pass up further (Bela Aug 7 2001)
case Event.SUSPECT:
// release the promise if rebroadcasting is in progress... otherwise we wait forever. there will be a new
// flush round anyway
if(rebroadcasting) {
cancelRebroadcasting();
}
break;
}
return up_prot.up(evt);
}
/* --------------------------------- Private Methods --------------------------------------- */
/**
* Adds the message to the sent_msgs table and then passes it down the stack. Change Bela Ban May 26 2002: we don't
* store a copy of the message, but a reference ! This saves us a lot of memory. However, this also means that a
* message should not be changed after storing it in the sent-table ! See protocols/DESIGN for details.
* Made seqno increment and adding to sent_msgs atomic, e.g. seqno won't get incremented if adding to
* sent_msgs fails e.g. due to an OOM (see http://jira.jboss.com/jira/browse/JGRP-179). bela Jan 13 2006
*/
protected void send(Event evt, Message msg) {
if(msg == null)
throw new NullPointerException("msg is null; event is " + evt);
if(!running) {
if(log.isTraceEnabled())
log.trace(local_addr + ": discarded message as we're not in the 'running' state, message: " + msg);
return;
}
long msg_id;
NakReceiverWindow win=xmit_table.get(local_addr);
if(win == null) { // discard message if there is no entry for local_addr
if(log.isWarnEnabled() && log_discard_msgs)
log.warn(local_addr + ": discarded message to " + local_addr + " with no window, my view is " + view);
return;
}
if(msg.getSrc() == null)
msg.setSrc(local_addr); // this needs to be done so we can check whether the message sender is the local_addr
msg_id=seqno.incrementAndGet();
long sleep=10;
while(running) {
try {
msg.putHeader(this.id, NakAckHeader.createMessageHeader(msg_id));
win.add(msg_id, msg);
break;
}
catch(Throwable t) {
if(running)
Util.sleep(sleep);
sleep=Math.min(5000, sleep*2);
}
}
// moved down_prot.down() out of synchronized clause (bela Sept 7 2006) http://jira.jboss.com/jira/browse/JGRP-300
if(log.isTraceEnabled())
log.trace("sending " + local_addr + "#" + msg_id);
down_prot.down(evt); // if this fails, since msg is in sent_msgs, it can be retransmitted
num_messages_sent++;
}
/**
* Finds the corresponding NakReceiverWindow and adds the message to it (according to seqno). Then removes as many
* messages as possible from the NRW and passes them up the stack. Discards messages from non-members.
*/
private void handleMessage(Message msg, NakAckHeader hdr) {
Address sender=msg.getSrc();
if(sender == null) {
if(log.isErrorEnabled())
log.error("sender of message is null");
return;
}
NakReceiverWindow win=xmit_table.get(sender);
if(win == null) { // discard message if there is no entry for sender
if(leaving)
return;
if(log.isWarnEnabled() && log_discard_msgs) {
if(suppress_log_non_member != null) {
suppress_log_non_member.log(SuppressLog.Level.warn, sender, suppress_time_non_member_warnings,
local_addr, hdr.seqno, sender, view);
}
else
log.warn(Util.getMessage("MsgDroppedNak"), local_addr, hdr.seqno, sender, view);
}
return;
}
num_messages_received++;
boolean loopback=local_addr.equals(sender);
boolean added=loopback || win.add(hdr.seqno, msg);
if(added && log.isTraceEnabled())
log.trace(new StringBuilder().append(local_addr).append(": received ").append(sender).append('#').append(hdr.seqno));
// OOB msg is passed up. When removed, we discard it. Affects ordering: http://jira.jboss.com/jira/browse/JGRP-379
if(added && msg.isFlagSet(Message.Flag.OOB)) {
if(loopback)
msg=win.get(hdr.seqno); // we *have* to get a message, because loopback means we didn't add it to win !
if(msg != null && msg.isFlagSet(Message.Flag.OOB)) {
if(msg.setTransientFlagIfAbsent(Message.OOB_DELIVERED)) {
if(log.isTraceEnabled())
log.trace(new StringBuilder().append(local_addr).append(": delivering ").append(sender).append('#').append(hdr.seqno));
try {
up_prot.up(new Event(Event.MSG, msg));
}
catch(Throwable t) {
log.error("failed to deliver OOB message " + msg, t);
}
}
}
}
// Efficient way of checking whether another thread is already processing messages from 'sender'.
// If that's the case, we return immediately and let the existing thread process our message
// (https://jira.jboss.org/jira/browse/JGRP-829). Benefit: fewer threads blocked on the same lock, these threads
// can be returned to the thread pool
final AtomicBoolean processing=win.getProcessing();
if(!processing.compareAndSet(false, true)) {
return;
}
boolean remove_msgs=discard_delivered_msgs && !loopback;
boolean released_processing=false;
try {
while(true) {
// we're removing a msg and set processing to false (if null) *atomically* (wrt to add())
List<Message> msgs=win.removeMany(processing, remove_msgs, max_msg_batch_size);
if(msgs == null || msgs.isEmpty()) {
released_processing=true;
if(rebroadcasting)
checkForRebroadcasts();
return;
}
for(final Message msg_to_deliver: msgs) {
// discard OOB msg if it has already been delivered (http://jira.jboss.com/jira/browse/JGRP-379)
if(msg_to_deliver.isFlagSet(Message.Flag.OOB) && !msg_to_deliver.setTransientFlagIfAbsent(Message.OOB_DELIVERED))
continue;
if(msg_to_deliver.isTransientFlagSet(Message.TransientFlag.DONT_LOOPBACK)
&& local_addr != null && local_addr.equals(msg.getSrc()))
continue;
//msg_to_deliver.removeHeader(getName()); // Changed by bela Jan 29 2003: not needed (see above)
try {
if(log.isTraceEnabled()) {
NakAckHeader header=(NakAckHeader)msg_to_deliver.getHeader(this.id);
log.trace(new StringBuilder().append(local_addr).append(": delivering ").append(sender).append('#').append(header.seqno));
}
up_prot.up(new Event(Event.MSG, msg_to_deliver));
}
catch(Throwable t) {
log.error("failed to deliver message " + msg_to_deliver, t);
}
}
}
}
finally {
// processing is always set in win.remove(processing) above and never here ! This code is just a
// 2nd line of defense should there be an exception before win.remove(processing) sets processing
if(!released_processing)
processing.set(false);
}
}
/**
* Retransmits messsages first_seqno to last_seqno from original_sender from xmit_table to xmit_requester,
* called when XMIT_REQ is received.
* @param xmit_requester The sender of the XMIT_REQ, we have to send the requested copy of the message to this address
* @param first_seqno The first sequence number to be retransmitted (<= last_seqno)
* @param last_seqno The last sequence number to be retransmitted (>= first_seqno)
* @param original_sender The member who originally sent the messsage. Guaranteed to be non-null
*/
private void handleXmitReq(Address xmit_requester, long first_seqno, long last_seqno, Address original_sender) {
if(first_seqno > last_seqno)
return;
if(log.isTraceEnabled()) {
StringBuilder sb=new StringBuilder();
sb.append(local_addr).append(": received xmit request from ").append(xmit_requester).append(" for ");
sb.append(original_sender).append(" [").append(first_seqno).append(" - ").append(last_seqno).append("]");
log.trace(sb.toString());
}
if(stats)
xmit_reqs_received.addAndGet(last_seqno - first_seqno +1);
NakReceiverWindow win=xmit_table.get(original_sender);
if(win == null) {
if(log.isErrorEnabled()) {
StringBuilder sb=new StringBuilder();
sb.append("(requester=").append(xmit_requester).append(", local_addr=").append(this.local_addr);
sb.append(") ").append(original_sender).append(" not found in retransmission table");
// don't print the table unless we are in trace mode because it can be LARGE
if (log.isTraceEnabled()) {
sb.append(":\n").append(printMessages());
}
if(print_stability_history_on_failed_xmit) {
sb.append(" (stability history:\n").append(printStabilityHistory());
}
log.error(sb.toString());
}
return;
}
long diff=last_seqno - first_seqno +1;
if(diff >= 10) {
List<Message> msgs=win.get(first_seqno, last_seqno);
if(msgs != null) {
for(Message msg: msgs)
sendXmitRsp(xmit_requester, msg);
}
}
else {
for(long i=first_seqno; i <= last_seqno; i++) {
Message msg=win.get(i);
if(msg == null) {
if(log.isWarnEnabled() && log_not_found_msgs && !local_addr.equals(xmit_requester)) {
StringBuilder sb=new StringBuilder();
sb.append("(requester=").append(xmit_requester).append(", local_addr=").append(this.local_addr);
sb.append(") message ").append(original_sender).append("::").append(i);
sb.append(" not found in retransmission table of ").append(original_sender).append(":\n").append(win);
if(print_stability_history_on_failed_xmit) {
sb.append(" (stability history:\n").append(printStabilityHistory());
}
log.warn(sb.toString());
}
continue;
}
sendXmitRsp(xmit_requester, msg);
}
}
}
private void cancelRebroadcasting() {
rebroadcast_lock.lock();
try {
rebroadcasting=false;
rebroadcast_done.signalAll();
}
finally {
rebroadcast_lock.unlock();
}
}
/**
* Flushes the queue. Done in a separate thread as we don't want to block the
* {@link ClientGmsImpl#installView(org.jgroups.View,org.jgroups.util.Digest)} method (called when a view is installed).
*/
protected void flushBecomeServerQueue() {
if(become_server_queue != null && !become_server_queue.isEmpty()) {
if(log.isTraceEnabled())
log.trace(local_addr + ": flushing become_server_queue (" + become_server_queue.size() + " elements)");
TP transport=getTransport();
Executor thread_pool=transport.getDefaultThreadPool(), oob_thread_pool=transport.getOOBThreadPool();
for(final Message msg: become_server_queue) {
Executor pool=msg.isFlagSet(Message.Flag.OOB)? oob_thread_pool : thread_pool;
pool.execute(new Runnable() {
public void run() {
try {
up(new Event(Event.MSG, msg));
}
finally {
become_server_queue.remove(msg);
}
}
});
}
}
}
/**
* Sends a message msg to the requester. We have to wrap the original message into a retransmit message, as we need
* to preserve the original message's properties, such as src, headers etc.
* @param dest
* @param msg
*/
private void sendXmitRsp(Address dest, Message msg) {
if(msg == null) {
if(log.isErrorEnabled())
log.error("message is null, cannot send retransmission");
return;
}
if(stats)
xmit_rsps_sent.incrementAndGet();
if(msg.getSrc() == null)
msg.setSrc(local_addr);
if(use_mcast_xmit) { // we simply send the original multicast message
down_prot.down(new Event(Event.MSG, msg));
return;
}
Message xmit_msg=msg.copy(true, true).dest(dest).setFlag(Message.Flag.INTERNAL); // copy payload and headers
NakAckHeader hdr=(NakAckHeader)xmit_msg.getHeader(id);
NakAckHeader newhdr=hdr.copy(); // create a copy of the header: https://issues.jboss.org/browse/JGRP-1502
newhdr.type=NakAckHeader.XMIT_RSP; // change the type in the copy from MSG --> XMIT_RSP
xmit_msg.putHeader(id, newhdr);
down_prot.down(new Event(Event.MSG, xmit_msg));
}
private void handleXmitRsp(Message msg, NakAckHeader hdr) {
if(msg == null)
return;
try {
if(stats)
xmit_rsps_received.incrementAndGet();
msg.setDest(null);
NakAckHeader newhdr=hdr.copy();
newhdr.type=NakAckHeader.MSG; // change the type back from XMIT_RSP --> MSG
msg.putHeader(id, newhdr);
up(new Event(Event.MSG, msg));
if(rebroadcasting)
checkForRebroadcasts();
}
catch(Exception ex) {
if(log.isErrorEnabled()) {
log.error("failed reading retransmitted message", ex);
}
}
}
/**
* Takes the argument highest_seqnos and compares it to the current digest. If the current digest has fewer messages,
* then send retransmit messages for the missing messages. Return when all missing messages have been received. If
* we're waiting for a missing message from P, and P crashes while waiting, we need to exclude P from the wait set.
*/
private void rebroadcastMessages() {
Digest their_digest;
long sleep=max_rebroadcast_timeout / NUM_REBROADCAST_MSGS;
long wait_time=max_rebroadcast_timeout, start=System.currentTimeMillis();
while(wait_time > 0) {
rebroadcast_digest_lock.lock();
try {
if(rebroadcast_digest == null)
break;
their_digest=rebroadcast_digest.copy();
}
finally {
rebroadcast_digest_lock.unlock();
}
Digest my_digest=getDigest();
boolean xmitted=false;
for(Digest.Entry entry: their_digest) {
Address member=entry.getMember();
long[] my_entry=my_digest.get(member);
if(my_entry == null)
continue;
long their_high=entry.getHighest();
// Cannot ask for 0 to be retransmitted because the first seqno in NAKACK and UNICAST(2) is always 1 !
// Also, we need to ask for retransmission of my_high+1, because we already *have* my_high, and don't
// need it, so the retransmission range is [my_high+1 .. their_high]: *exclude* my_high, but *include*
// their_high
long my_high=Math.max(my_entry[0], my_entry[1]);
if(their_high > my_high) {
if(log.isTraceEnabled())
log.trace("[" + local_addr + "] fetching " + my_high + "-" + their_high + " from " + member);
retransmit(my_high+1, their_high, member, true); // use multicast to send retransmit request
xmitted=true;
}
}
if(!xmitted)
return; // we're done; no retransmissions are needed anymore. our digest is >= rebroadcast_digest
rebroadcast_lock.lock();
try {
try {
my_digest=getDigest();
rebroadcast_digest_lock.lock();
try {
if(!rebroadcasting || isGreaterThanOrEqual(my_digest,rebroadcast_digest))
return;
}
finally {
rebroadcast_digest_lock.unlock();
}
rebroadcast_done.await(sleep, TimeUnit.MILLISECONDS);
wait_time-=(System.currentTimeMillis() - start);
}
catch(InterruptedException e) {
}
}
finally {
rebroadcast_lock.unlock();
}
}
}
protected void checkForRebroadcasts() {
Digest tmp=getDigest();
boolean cancel_rebroadcasting;
rebroadcast_digest_lock.lock();
try {
cancel_rebroadcasting=isGreaterThanOrEqual(tmp,rebroadcast_digest);
}
finally {
rebroadcast_digest_lock.unlock();
}
if(cancel_rebroadcasting) {
cancelRebroadcasting();
}
}
/**
* Returns true if all senders of the current digest have their seqnos >= the ones from other
*/
protected static boolean isGreaterThanOrEqual(Digest first, Digest other) {
if(other == null)
return true;
for(Digest.Entry entry: first) {
Address sender=entry.getMember();
long[] their_entry=other.get(sender);
if(their_entry == null)
continue;
long my_highest=entry.getHighest();
long their_highest=Math.max(their_entry[0],their_entry[1]);
if(my_highest < their_highest)
return false;
}
return true;
}
/**
* Remove old members from NakReceiverWindows. Essentially removes all entries from xmit_table that are not
* in <code>members</code>. This method is not called concurrently multiple times
*/
private void adjustReceivers(List<Address> members) {
Set<Address> keys=xmit_table.keySet();
for(Address member: keys) {
if(!members.contains(member)) {
if(local_addr != null && local_addr.equals(member))
continue;
NakReceiverWindow win=xmit_table.remove(member);
if(win != null) {
win.destroy();
log.debug("%s: removed %s from xmit_table (not member anymore)", local_addr, member);
}
}
}
for(Address member: this.members)
if(!keys.contains(member))
xmit_table.putIfAbsent(member, createNakReceiverWindow(member, 0));
}
/**
* Returns a message digest: for each member P the highest delivered and received seqno is added
*/
public Digest getDigest() {
final Map<Address,long[]> map=new HashMap<Address,long[]>();
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
Address sender=entry.getKey(); // guaranteed to be non-null (CCHM)
NakReceiverWindow win=entry.getValue(); // guaranteed to be non-null (CCHM)
long[] seqnos=win.getDigest();
map.put(sender, seqnos);
}
return new Digest(map);
}
public Digest getDigest(Address mbr) {
if(mbr == null)
return getDigest();
NakReceiverWindow win=xmit_table.get(mbr);
if(win == null)
return null;
long[] seqnos=win.getDigest();
return new Digest(mbr, seqnos[0], seqnos[1]);
}
/**
* Creates a NakReceiverWindow for each sender in the digest according to the sender's seqno. If NRW already exists,
* reset it.
*/
private void setDigest(Digest digest) {
setDigest(digest, false);
}
/**
* For all members of the digest, adjust the NakReceiverWindows in xmit_table. If no entry
* exists, create one with the initial seqno set to the seqno of the member in the digest. If the member already
* exists, and is not the local address, replace it with the new entry (http://jira.jboss.com/jira/browse/JGRP-699)
* if the digest's seqno is greater than the seqno in the window.
*/
private void mergeDigest(Digest digest) {
setDigest(digest, true);
}
/**
* Overwrites existing entries, but does NOT remove entries not found in the digest
* @param digest
*/
private void overwriteDigest(final Digest digest) {
if(digest == null)
return;
StringBuilder sb=new StringBuilder("\n[overwriteDigest()]\n");
sb.append("existing digest: " + getDigest()).append("\nnew digest: " + digest);
for(Digest.Entry entry: digest) {
Address member=entry.getMember();
if(member == null)
continue;
long highest_delivered_seqno=entry.getHighestDeliveredSeqno();
NakReceiverWindow win=xmit_table.get(member);
if(win != null) {
if(local_addr.equals(member)) {
// Adjust the highest_delivered seqno (to send msgs again): https://jira.jboss.org/browse/JGRP-1251
win.setHighestDelivered(highest_delivered_seqno);
continue; // don't destroy my own window
}
xmit_table.remove(member);
win.destroy(); // stops retransmission
}
win=createNakReceiverWindow(member, highest_delivered_seqno);
xmit_table.put(member, win);
}
sb.append("\n").append("resulting digest: " + getDigest().toString(digest));
digest_history.add(sb.toString());
if(log.isDebugEnabled())
log.debug(sb.toString());
}
/**
* Sets or merges the digest. If there is no entry for a given member in xmit_table, create a new NakReceiverWindow.
* Else skip the existing entry, unless it is a merge. In this case, skip the existing entry if its seqno is
* greater than or equal to the one in the digest, or reset the window and create a new one if not.
* @param digest The digest
* @param merge Whether to merge the new digest with our own, or not
*/
private void setDigest(final Digest digest, boolean merge) {
if(digest == null)
return;
StringBuilder sb=new StringBuilder(merge? "\n[" + local_addr + " mergeDigest()]\n" : "\n["+local_addr + " setDigest()]\n");
sb.append("existing digest: " + getDigest()).append("\nnew digest: " + digest);
boolean set_own_seqno=false;
for(Digest.Entry entry: digest) {
Address member=entry.getMember();
if(member == null)
continue;
long highest_delivered_seqno=entry.getHighestDeliveredSeqno();
NakReceiverWindow win=xmit_table.get(member);
if(win != null) {
// We only reset the window if its seqno is lower than the seqno shipped with the digest. Also, we
// don't reset our own window (https://jira.jboss.org/jira/browse/JGRP-948, comment 20/Apr/09 03:39 AM)
if(!merge
|| (local_addr != null && local_addr.equals(member)) // never overwrite our own entry
|| win.getHighestDelivered() >= highest_delivered_seqno) // my seqno is >= digest's seqno for sender
continue;
xmit_table.remove(member);
win.destroy(); // stops retransmission
// to get here, merge must be false !
if(member.equals(local_addr)) { // Adjust the seqno: https://jira.jboss.org/browse/JGRP-1251
seqno.set(highest_delivered_seqno);
set_own_seqno=true;
}
}
win=createNakReceiverWindow(member, highest_delivered_seqno);
xmit_table.put(member, win);
}
sb.append("\n").append("resulting digest: " + getDigest().toString(digest));
if(set_own_seqno)
sb.append("\nnew seqno for " + local_addr + ": " + seqno);
digest_history.add(sb.toString());
if(log.isDebugEnabled())
log.debug(sb.toString());
}
private NakReceiverWindow createNakReceiverWindow(Address sender, long initial_seqno) {
NakReceiverWindow win=new NakReceiverWindow(sender, this, initial_seqno, timer, use_range_based_retransmitter,
xmit_table_num_rows, xmit_table_msgs_per_row,
xmit_table_resize_factor, xmit_table_max_compaction_time, false);
if(exponential_backoff > 0)
win.setRetransmitTimeouts(new ExponentialInterval(exponential_backoff));
else
win.setRetransmitTimeouts(new StaticInterval(retransmit_timeouts));
if(xmit_stagger_timeout > 0)
win.setXmitStaggerTimeout(xmit_stagger_timeout);
return win;
}
/**
* Garbage collect messages that have been seen by all members. Update sent_msgs: for the sender P in the digest
* which is equal to the local address, garbage collect all messages <= seqno at digest[P]. Update xmit_table:
* for each sender P in the digest and its highest seqno seen SEQ, garbage collect all delivered_msgs in the
* NakReceiverWindow corresponding to P which are <= seqno at digest[P].
*/
private void stable(Digest digest) {
NakReceiverWindow recv_win;
long my_highest_rcvd; // highest seqno received in my digest for a sender P
long stability_highest_rcvd; // highest seqno received in the stability vector for a sender P
if(members == null || local_addr == null || digest == null) {
log.warn("members, local_addr or digest are null !");
return;
}
if(log.isTraceEnabled()) {
log.trace("received stable digest " + digest);
}
stability_msgs.add(digest.toString());
long high_seqno_delivered, high_seqno_received;
for(Digest.Entry entry: digest) {
Address member=entry.getMember();
if(member == null)
continue;
high_seqno_delivered=entry.getHighestDeliveredSeqno();
high_seqno_received=entry.getHighestReceivedSeqno();
// check whether the last seqno received for a sender P in the stability vector is > last seqno
// received for P in my digest. if yes, request retransmission (see "Last Message Dropped" topic
// in DESIGN)
recv_win=xmit_table.get(member);
if(recv_win != null) {
my_highest_rcvd=recv_win.getHighestReceived();
stability_highest_rcvd=high_seqno_received;
if(stability_highest_rcvd >= 0 && stability_highest_rcvd > my_highest_rcvd) {
if(log.isTraceEnabled()) {
log.trace("my_highest_rcvd (" + my_highest_rcvd + ") < stability_highest_rcvd (" +
stability_highest_rcvd + "): requesting retransmission of " +
member + '#' + stability_highest_rcvd);
}
retransmit(stability_highest_rcvd, stability_highest_rcvd, member);
}
}
if(high_seqno_delivered < 0)
continue;
if(log.isTraceEnabled())
log.trace("deleting msgs <= " + high_seqno_delivered + " from " + member);
// delete *delivered* msgs that are stable
if(recv_win != null)
recv_win.stable(high_seqno_delivered); // delete all messages with seqnos <= seqno
}
}
/* ---------------------- Interface Retransmitter.RetransmitCommand ---------------------- */
/**
* Implementation of Retransmitter.RetransmitCommand. Called by retransmission thread when gap is detected.
*/
public void retransmit(long first_seqno, long last_seqno, Address sender) {
if(first_seqno <= last_seqno)
retransmit(first_seqno, last_seqno, sender, false);
}
protected void retransmit(long first_seqno, long last_seqno, final Address sender, boolean multicast_xmit_request) {
Address dest=sender; // to whom do we send the XMIT request ?
if(multicast_xmit_request || this.use_mcast_xmit_req) {
dest=null;
}
else {
if(xmit_from_random_member && !local_addr.equals(sender)) {
Address random_member=(Address)Util.pickRandomElement(members);
if(random_member != null && !local_addr.equals(random_member)) {
dest=random_member;
if(log.isTraceEnabled())
log.trace("picked random member " + dest + " to send XMIT request to");
}
}
}
NakAckHeader hdr=NakAckHeader.createXmitRequestHeader(first_seqno, last_seqno, sender);
Message retransmit_msg=new Message(dest).setFlag(Message.Flag.OOB, Message.Flag.INTERNAL);
if(log.isTraceEnabled())
log.trace(local_addr + ": sending XMIT_REQ ([" + first_seqno + ", " + last_seqno + "]) to " + dest);
retransmit_msg.putHeader(this.id, hdr);
down_prot.down(new Event(Event.MSG, retransmit_msg));
if(stats)
xmit_reqs_sent.addAndGet(last_seqno - first_seqno +1);
}
/* ------------------- End of Interface Retransmitter.RetransmitCommand -------------------- */
private void reset() {
seqno.set(0);
for(NakReceiverWindow win: xmit_table.values())
win.destroy();
xmit_table.clear();
}
@ManagedOperation(description="Prints the contents of the receiver windows for all members")
public String printMessages() {
StringBuilder ret=new StringBuilder(local_addr + ":\n");
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
Address addr=entry.getKey();
NakReceiverWindow win=entry.getValue();
ret.append(addr).append(": ").append(win.toString()).append('\n');
}
return ret.toString();
}
// ProbeHandler interface
public Map<String, String> handleProbe(String... keys) {
Map<String,String> retval=new HashMap<String,String>();
for(String key: keys) {
if(key.equals("digest-history"))
retval.put(key, printDigestHistory());
if(key.equals("dump-digest"))
retval.put(key, "\n" + printMessages());
}
return retval;
}
// ProbeHandler interface
public String[] supportedKeys() {
return new String[]{"digest-history", "dump-digest"};
}
/* ----------------------------- End of Private Methods ------------------------------------ */
}