fix copyOf bug

Author: shangm2

presto-common/src/main/java/com/facebook/presto/common/RuntimeMetric.java

@@ -226,9 +226,15 @@ private static long determineBucketWidth(RuntimeUnit unit)
     }
 
     public static RuntimeMetric copyOf(RuntimeMetric metric)
+    {
+        return copyOf(metric, metric.getName());
+    }
+
+    public static RuntimeMetric copyOf(RuntimeMetric metric, String newName)
     {
         requireNonNull(metric, "metric is null");
-        RuntimeMetric copy = new RuntimeMetric(metric.getName(), metric.getUnit(),
+        requireNonNull(newName, "newName is null");
+        RuntimeMetric copy = new RuntimeMetric(newName, metric.getUnit(),
                 metric.percentileTrackingEnabled, metric.bucketWidth, metric.numBuckets);
         copy.set(metric.getSum(), metric.getCount(), metric.getMax(), metric.getMin());
         if (metric.histogramBuckets != null) {

presto-common/src/main/java/com/facebook/presto/common/RuntimeStats.java

@@ -116,7 +116,7 @@ public void mergeMetric(String name, RuntimeMetric metric)
         RuntimeMetric existing = metrics.get(name);
         if (existing == null) {
             // First time seeing this metric - create a copy to preserve configuration
-            metrics.put(name, RuntimeMetric.copyOf(metric));
+            metrics.put(name, RuntimeMetric.copyOf(metric, name));
         }
         else {
             // Metric already exists - merge into it
@@ -157,13 +157,11 @@ public void update(RuntimeStats stats)
         stats.getMetrics().forEach((name, newMetric) -> {
             RuntimeMetric existing = metrics.get(name);
             if (existing == null) {
-                // First time seeing this metric - create with matching configuration to avoid set() validation errors
-                // Use basic constructor without percentile tracking (update is for stats only, not config)
-                RuntimeMetric created = new RuntimeMetric(name, newMetric.getUnit(), false, newMetric.getBucketWidth(), newMetric.getNumBuckets());
-                created.set(newMetric);
-                metrics.put(name, created);
+                // First time seeing this metric - copy it entirely to establish configuration
+                metrics.put(name, RuntimeMetric.copyOf(newMetric));
             }
             else {
+                // Metric exists - update values only (set() validates matching configurations)
                 existing.set(newMetric);
             }
         });