Extended technical report View change protocol

Author: Tezzish

simulator/src/main/java/byzzbench/simulator/protocols/Zyzzyva/MessageLog.java

@@ -76,11 +76,16 @@ public MessageLog() {
         this.setLastCheckpoint(0L);
     }
 
-    public List<OrderedRequestMessageWrapper> getOrderedRequestHistory(long sequenceNumber) {
-        ArrayList<OrderedRequestMessageWrapper> orderedRequestHistory = new ArrayList<>();
+    /**
+     * Get the ordered request history from the sequence number to the end of the ordered messages
+     * @param sequenceNumber - the sequence number to start the history from
+     * @return - a map of the ordered request history with the sequence number as the key
+     */
+    public SortedMap<Long, OrderedRequestMessageWrapper> getOrderedRequestHistory(long sequenceNumber) {
+        SortedMap<Long, OrderedRequestMessageWrapper> orderedRequestHistory = new TreeMap<>();
         long maxSeqNum = this.getOrderedMessages().isEmpty() ? 0 : this.getOrderedMessages().lastKey();
         for (long i = sequenceNumber + 1; i <= maxSeqNum; i++) {
-            orderedRequestHistory.add(this.orderedMessages.get(i));
+            orderedRequestHistory.put(i, this.orderedMessages.get(i));
         }
         return orderedRequestHistory;
     }
@@ -194,6 +199,10 @@ public void putRequestCache(String clientId, RequestMessage rm, SpeculativeRespo
         this.getResponseCache().put(clientId, new ImmutablePair<>(rm, srw));
     }
 
+    public void putOrderedRequestMessageWrapper(OrderedRequestMessageWrapper ormw) {
+        this.getOrderedMessages().put(ormw.getOrderedRequest().getSequenceNumber(), ormw);
+    }
+
     public long highestTimestampInCacheForClient(String clientId) {
         if (!this.getResponseCache().containsKey(clientId)) {
             return -1;

simulator/src/main/java/byzzbench/simulator/protocols/Zyzzyva/SpeculativeHistory.java

@@ -1,6 +1,8 @@
 package byzzbench.simulator.protocols.Zyzzyva;
 
 import java.util.LinkedHashMap;
+import java.util.Map;
+
 import lombok.extern.java.Log;
 
 @Log
@@ -90,6 +92,10 @@ public boolean has(long index) {
         return this.speculativeHistory.containsKey(index);
     }
 
+    public Map.Entry<Long, Long> getLastEntry() {
+        return this.speculativeHistory.lastEntry();
+    }
+
     /**
      * Get the length of the speculative history
      * @return the length of the speculative history

simulator/src/main/java/byzzbench/simulator/protocols/Zyzzyva/ZyzzyvaReplica.java

@@ -5,13 +5,19 @@
 import lombok.With;
 
 import java.util.Collection;
+import java.util.List;
+import java.util.SortedMap;
+import java.util.SortedSet;
 
 @Data
 @EqualsAndHashCode(callSuper = true)
 @With
 public class NewViewMessage extends MessagePayload {
     private final long futureViewNumber;
-    private final Collection<ViewChangeMessage> viewChangeMessages;
+    // ReplicaId -> ViewChangeMessage
+    private final SortedMap<String, ViewChangeMessage> viewChangeMessages;
+    // SequenceNumber -> OrderedRequestMessageWrapper
+    private final SortedMap<Long, OrderedRequestMessageWrapper> orderedRequestHistory;
 
     @Override
     public String getType() {

simulator/src/main/java/byzzbench/simulator/protocols/Zyzzyva/message/NewViewMessage.java

@@ -8,12 +8,21 @@
 
 @Data
 @With
-public class OrderedRequestMessage extends MessagePayload {
+public class OrderedRequestMessage extends MessagePayload implements Comparable<OrderedRequestMessage> {
     private final long viewNumber;
     private final long sequenceNumber;
     private final long history;
     private final byte[] digest;
 
+    @Override
+    public int compareTo(OrderedRequestMessage o) {
+        if (this.viewNumber != o.viewNumber) {
+            return Long.compare(this.viewNumber, o.viewNumber);
+        }
+        return Long.compare(this.sequenceNumber, o.sequenceNumber);
+    }
+
+
     @Override
     public boolean equals(Object obj) {
         if (obj instanceof OrderedRequestMessage other) {

simulator/src/main/java/byzzbench/simulator/protocols/Zyzzyva/message/OrderedRequestMessage.java

@@ -8,10 +8,29 @@
 @Data
 @EqualsAndHashCode(callSuper = true)
 @With
-public class OrderedRequestMessageWrapper extends MessagePayload {
+public class OrderedRequestMessageWrapper extends MessagePayload implements Comparable<OrderedRequestMessageWrapper> {
     private final OrderedRequestMessage orderedRequest;
     private final RequestMessage requestMessage;
 
+    @Override
+    public int compareTo(OrderedRequestMessageWrapper o) {
+        return orderedRequest.compareTo(o.getOrderedRequest());
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof OrderedRequestMessageWrapper other) {
+            return orderedRequest.equals(other.getOrderedRequest()) &&
+                    requestMessage.equals(other.getRequestMessage());
+        }
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return orderedRequest.hashCode() ^ requestMessage.hashCode();
+    }
+
     @Override
     public String getType() {
         return "ORDERED_REQUEST";

simulator/src/main/java/byzzbench/simulator/protocols/Zyzzyva/message/OrderedRequestMessageWrapper.java

@@ -1,24 +1,30 @@
 package byzzbench.simulator.protocols.Zyzzyva.message;
 
+import byzzbench.simulator.protocols.Zyzzyva.CommitCertificate;
 import byzzbench.simulator.transport.MessagePayload;
 import lombok.Data;
 import lombok.EqualsAndHashCode;
 import lombok.With;
 
 import java.io.Serializable;
 import java.util.List;
+import java.util.SortedMap;
+import java.util.SortedSet;
 
 @Data
 @EqualsAndHashCode(callSuper = true)
 @With
 public class ViewChangeMessage extends MessagePayload {
     private final long futureViewNumber;
+    private final long stableCheckpoint;
+    /// TODO: initialize the message log with checkpoint messages
+    private final List<CheckpointMessage> checkpoints;
     // CC is either the most recent commit certificate for a request since the last view change,
     // f + 1 view-confirm messages if no commit certificate is available,
     // or a new-view message if neither of the previous options are available.
-    private final Serializable commitCertificate;
+    private final CommitCertificate commitCertificate;
     // O is i’s ordered request history since the commit certificate indicated by CC
-    private final List<OrderedRequestMessageWrapper> orderedRequestHistory;
+    private final SortedMap<Long, OrderedRequestMessageWrapper> orderedRequestHistory;
     private final String replicaId;
 
     @Override