diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixConsistentMapService.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixConsistentMapService.java
index fe5a2a9..9d72be5 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixConsistentMapService.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixConsistentMapService.java
@@ -337,7 +337,11 @@
         String key = commit.value().key();
         MapEntryValue oldValue = entries().get(key);
         MapEntryValue newValue = new MapEntryValue(MapEntryValue.Type.VALUE, commit.index(), commit.value().value());
+
+        // If the value is null or a tombstone, this is an insert.
+        // Otherwise, only update the value if it has changed to reduce the number of events.
         if (valueIsNull(oldValue)) {
+            // If the key has been locked by a transaction, return a WRITE_LOCK error.
             if (preparedKeys.contains(key)) {
                 return new MapEntryUpdateResult<>(
                         MapEntryUpdateResult.Status.WRITE_LOCK,
@@ -351,6 +355,7 @@
             publish(new MapEvent<>(MapEvent.Type.INSERT, "", key, toVersioned(newValue), result));
             return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.OK, commit.index(), key, result);
         } else if (!valuesEqual(oldValue, newValue)) {
+            // If the key has been locked by a transaction, return a WRITE_LOCK error.
             if (preparedKeys.contains(key)) {
                 return new MapEntryUpdateResult<>(
                         MapEntryUpdateResult.Status.WRITE_LOCK,
@@ -364,6 +369,7 @@
             publish(new MapEvent<>(MapEvent.Type.UPDATE, "", key, toVersioned(newValue), result));
             return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.OK, commit.index(), key, result);
         }
+        // If the value hasn't changed, return a NOOP result.
         return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.NOOP, commit.index(), key, toVersioned(oldValue));
     }
 
@@ -376,7 +382,10 @@
     protected MapEntryUpdateResult<String, byte[]> putIfAbsent(Commit<? extends Put> commit) {
         String key = commit.value().key();
         MapEntryValue oldValue = entries().get(key);
+
+        // If the value is null, this is an INSERT.
         if (valueIsNull(oldValue)) {
+            // If the key has been locked by a transaction, return a WRITE_LOCK error.
             if (preparedKeys.contains(key)) {
                 return new MapEntryUpdateResult<>(
                         MapEntryUpdateResult.Status.WRITE_LOCK,
@@ -388,13 +397,16 @@
                     MapEntryValue.Type.VALUE,
                     commit.index(),
                     commit.value().value());
-            entries().put(commit.value().key(),
-                    new MapEntryValue(MapEntryValue.Type.VALUE, newValue.version(), newValue.value()));
+            entries().put(commit.value().key(), newValue);
             Versioned<byte[]> result = toVersioned(newValue);
             publish(new MapEvent<>(MapEvent.Type.INSERT, "", key, result, null));
             return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.OK, commit.index(), key, null);
         }
-        return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.NOOP, commit.index(), key, toVersioned(oldValue));
+        return new MapEntryUpdateResult<>(
+                MapEntryUpdateResult.Status.PRECONDITION_FAILED,
+                commit.index(),
+                key,
+                toVersioned(oldValue));
     }
 
     /**
@@ -407,7 +419,11 @@
         String key = commit.value().key();
         MapEntryValue oldValue = entries().get(key);
         MapEntryValue newValue = new MapEntryValue(MapEntryValue.Type.VALUE, commit.index(), commit.value().value());
+
+        // If the value is null or a tombstone, this is an insert.
+        // Otherwise, only update the value if it has changed to reduce the number of events.
         if (valueIsNull(oldValue)) {
+            // If the key has been locked by a transaction, return a WRITE_LOCK error.
             if (preparedKeys.contains(key)) {
                 return new MapEntryUpdateResult<>(
                         MapEntryUpdateResult.Status.WRITE_LOCK,
@@ -420,6 +436,7 @@
             publish(new MapEvent<>(MapEvent.Type.INSERT, "", key, result, null));
             return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.OK, commit.index(), key, result);
         } else if (!valuesEqual(oldValue, newValue)) {
+            // If the key has been locked by a transaction, return a WRITE_LOCK error.
             if (preparedKeys.contains(key)) {
                 return new MapEntryUpdateResult<>(
                         MapEntryUpdateResult.Status.WRITE_LOCK,
@@ -445,15 +462,26 @@
      */
     private MapEntryUpdateResult<String, byte[]> removeIf(long index, String key, Predicate<MapEntryValue> predicate) {
         MapEntryValue value = entries().get(key);
-        if (value == null || !predicate.test(value)) {
-            return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.NOOP, index, key, null);
+
+        // If the value does not exist or doesn't match the predicate, return a PRECONDITION_FAILED error.
+        if (valueIsNull(value) || !predicate.test(value)) {
+            return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.PRECONDITION_FAILED, index, key, null);
         }
-        entries().remove(key);
-        if (!activeTransactions.isEmpty()) {
-            entries().put(key, new MapEntryValue(MapEntryValue.Type.TOMBSTONE, value.version, null));
+
+        // If the key has been locked by a transaction, return a WRITE_LOCK error.
+        if (preparedKeys.contains(key)) {
+            return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.WRITE_LOCK, index, key, null);
         }
+
+        // If no transactions are active, remove the key. Otherwise, replace it with a tombstone.
+        if (activeTransactions.isEmpty()) {
+            entries().remove(key);
+        } else {
+            entries().put(key, new MapEntryValue(MapEntryValue.Type.TOMBSTONE, index, null));
+        }
+
         Versioned<byte[]> result = toVersioned(value);
-        publish(Lists.newArrayList(new MapEvent<>(MapEvent.Type.REMOVE, "", key, null, result)));
+        publish(new MapEvent<>(MapEvent.Type.REMOVE, "", key, null, result));
         return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.OK, index, key, result);
     }
 
@@ -500,15 +528,24 @@
     private MapEntryUpdateResult<String, byte[]> replaceIf(
             long index, String key, MapEntryValue newValue, Predicate<MapEntryValue> predicate) {
         MapEntryValue oldValue = entries().get(key);
-        if (oldValue == null) {
-            return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.NOOP, index, key, null);
+
+        // If the key is not set or the current value doesn't match the predicate, return a PRECONDITION_FAILED error.
+        if (valueIsNull(oldValue) || !predicate.test(oldValue)) {
+            return new MapEntryUpdateResult<>(
+                    MapEntryUpdateResult.Status.PRECONDITION_FAILED,
+                    index,
+                    key,
+                    toVersioned(oldValue));
         }
-        if (!predicate.test(oldValue)) {
-            return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.NOOP, index, key, toVersioned(oldValue));
+
+        // If the key has been locked by a transaction, return a WRITE_LOCK error.
+        if (preparedKeys.contains(key)) {
+            return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.WRITE_LOCK, index, key, null);
         }
+
         entries().put(key, newValue);
         Versioned<byte[]> result = toVersioned(oldValue);
-        publish(Lists.newArrayList(new MapEvent<>(MapEvent.Type.UPDATE, "", key, toVersioned(newValue), result)));
+        publish(new MapEvent<>(MapEvent.Type.UPDATE, "", key, toVersioned(newValue), result));
         return new MapEntryUpdateResult<>(MapEntryUpdateResult.Status.OK, index, key, result);
     }