go/storage/mkvs: Don't try to sync dirty keys

go/storage/mkvs/urkel/lookup.go

@@ -17,6 +17,13 @@ func (t *tree) Get(ctx context.Context, key []byte) ([]byte, error) {
 		return nil, ErrClosed
 	}
 
+	// If the key has been modified locally, no need to perform any lookups.
+	if !t.withoutWriteLog {
+		if entry := t.pendingWriteLog[node.ToMapKey(key)]; entry != nil {
+			return entry.value, nil
+		}
+	}
+
 	// Remember where the path from root to target node ends (will end).
 	t.cache.markPosition()
 

go/storage/mkvs/urkel/remove.go

@@ -16,6 +16,14 @@ func (t *tree) RemoveExisting(ctx context.Context, key []byte) ([]byte, error) {
 		return nil, ErrClosed
 	}
 
+	// If the key has already been removed locally, don't try to remove it again.
+	var entry *pendingEntry
+	if !t.withoutWriteLog {
+		if entry = t.pendingWriteLog[node.ToMapKey(key)]; entry != nil && entry.value == nil {
+			return nil, nil
+		}
+	}
+
 	// Remember where the path from root to target node ends (will end).
 	t.cache.markPosition()
 
@@ -26,7 +34,6 @@ func (t *tree) RemoveExisting(ctx context.Context, key []byte) ([]byte, error) {
 
 	// Update the pending write log.
 	if !t.withoutWriteLog {
-		entry := t.pendingWriteLog[node.ToMapKey(key)]
 		if entry == nil {
 			t.pendingWriteLog[node.ToMapKey(key)] = &pendingEntry{key, nil, changed, nil}
 		} else {

go/storage/mkvs/urkel/testdata/case-5.json

@@ -0,0 +1,18 @@
+[
+    {
+        "op": "Insert",
+        "key": "AwAA"
+    },
+    {
+        "op": "Insert",
+        "key": "AwAe"
+    },
+    {
+        "op": "Insert",
+        "key": "AAAe"
+    },
+    {
+        "op": "Remove",
+        "key": "AAAe"
+    }
+]

go/storage/mkvs/urkel/urkel_test.go

@@ -1872,6 +1872,10 @@ func testSpecialCase4(t *testing.T, ndb db.NodeDB, factory NodeDBFactory) {
 	testSpecialCaseFromJSON(t, ndb, "case-4.json")
 }
 
+func testSpecialCase5(t *testing.T, ndb db.NodeDB, factory NodeDBFactory) {
+	testSpecialCaseFromJSON(t, ndb, "case-5.json")
+}
+
 func testBackend(
 	t *testing.T,
 	initBackend func(t *testing.T) (NodeDBFactory, func()),
@@ -1911,6 +1915,7 @@ func testBackend(
 		{"SpecialCase2", testSpecialCase2},
 		{"SpecialCase3", testSpecialCase3},
 		{"SpecialCase4", testSpecialCase4},
+		{"SpecialCase5", testSpecialCase5},
 		{"Errors", testErrors},
 	}
 

runtime/src/storage/mkvs/urkel/tree/lookup.rs

@@ -49,6 +49,11 @@ impl UrkelTree {
         let boxed_key = key.to_vec();
         let pending_root = self.cache.borrow().get_pending_root();
 
+        // If the key has been modified locally, no need to perform any lookups.
+        if let Some(PendingLogEntry { ref value, .. }) = self.pending_write_log.get(&boxed_key) {
+            return Ok(value.clone());
+        }
+
         // Remember where the path from root to target node ends (will end).
         self.cache.borrow_mut().mark_position();
 

runtime/src/storage/mkvs/urkel/tree/remove.rs

@@ -14,6 +14,11 @@ impl UrkelTree {
         let boxed_key = key.to_vec();
         let pending_root = self.cache.borrow().get_pending_root();
 
+        // If the key has already been removed locally, don't try to remove it again.
+        if let Some(PendingLogEntry { value: None, .. }) = self.pending_write_log.get(&boxed_key) {
+            return Ok(None);
+        }
+
         // Remember where the path from root to target node ends (will end).
         self.cache.borrow_mut().mark_position();