Updated with new metrics

Author: orspod

articles/data-explorer/using-metrics.md

@@ -46,7 +46,11 @@ In the Metrics pane:
     | Ingestion volume (in MB) | Count | Max, Min, Sum | The total size of data ingested to the cluster (in MB) before compression. |
     | Keep alive | Count | Avg | Tracks the responsiveness of the cluster. A fully responsive cluster returns value 1 and a blocked or disconnected cluster returns 0. |
     | Query duration | Seconds | Count, Avg, Min, Max, Sum | Total time until query results are received (doesn't include network latency). |
-    | | | |
+    | Total number of concurrent queries | Count | Avg, Max, Min, Sum | The number of queries run in parallel in the cluster. This metric is a good way to estimate the load on the cluster. |
+    | Total number of throttled queries | Count | Avg, Max, Min, Sum | The number of throttled (rejected) queries in the cluster. The maximum number of concurrent (parallel) queries allowed is defined in the concurrent query policy. |
+    | Total number of throttled commands | Count | Avg, Max, Min, Sum | The number of throttled (rejected) commands in the cluster, since the maximum allowed number of concurrent (parallel) commands was reached. |
+    | Total number of extents | Count | Avg, Max, Min, Sum | Total number of data extents in the cluster. Changes in this metric can imply massive data structure changes and high load on the cluster, since merging data extents is a CPU-heavy activity |
+    | | | | |
 
     Additional information regarding [supported Azure Data Explorer cluster metrics](/azure/azure-monitor/platform/metrics-supported#microsoftkustoclusters)