diff --git a/CHANGELOG.md b/CHANGELOG.md
index 96fcb5cb..5b6f62b9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,10 @@ project adheres to [Semantic Versioning](http://semver.org/).
 ### Breaking
 
 ### Changed
+  - Changes for cluster mode
+  - Removed `byLabels` Grouper in `metricAggregators.js` file and created a global Map to avoid Map creation on every request for the metrics
+  - Moved hashing of labels from master to worker to distribute the cpu bound hashing among workers
+  - Workers to write metrics in tmp file and send the file name to master to read metrics from rather than sending on IPC to keep IPC congestion free. (change in `cluster.js`)
 
 ### Added
 
diff --git a/lib/cluster.js b/lib/cluster.js
index 996aff1b..b0576ada 100644
--- a/lib/cluster.js
+++ b/lib/cluster.js
@@ -219,7 +219,8 @@ function addListeners() {
 								value["hash"] = key;
 							});
 						});
-						const filename = path.join(os.tmpdir(), `metrics-${process.pid}}.json`);
+						// adding request id in file path to handle concurrency
+						const filename = path.join(os.tmpdir(), `metrics-${process.pid}-${message.requestId}.json`);
 						fs.writeFile(filename, JSON.stringify(metrics), (err) => {
 							if(err) {
 								process.send({