SendBatch: Add histogram metric for RegionServers per Batch

prometheus.go

@@ -10,16 +10,28 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promauto"
 )
 
-var operationDurationSeconds = promauto.NewHistogramVec(
-	prometheus.HistogramOpts{
-		Namespace: "gohbase",
-		Name:      "operation_duration_seconds",
-		Help:      "Time in seconds for operation to complete",
-		//   >>> [0.04*(2**i) for i in range(11)]
-		//   [0.04, 0.08, 0.16, 0.32, 0.64, 1.28, 2.56, 5.12, 10.24, 20.48, 40.96]
-		// Meaning 40ms, 80ms, 160ms, 320ms, 640ms, 1.28s, ... max 40.96s
-		// (most requests have a 30s timeout by default at the Envoy level)
-		Buckets: prometheus.ExponentialBuckets(0.04, 2, 11),
-	},
-	[]string{"operation", "result"},
+var (
+	operationDurationSeconds = promauto.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "gohbase",
+			Name:      "operation_duration_seconds",
+			Help:      "Time in seconds for operation to complete",
+			//   >>> [0.04*(2**i) for i in range(11)]
+			//   [0.04, 0.08, 0.16, 0.32, 0.64, 1.28, 2.56, 5.12, 10.24, 20.48, 40.96]
+			// Meaning 40ms, 80ms, 160ms, 320ms, 640ms, 1.28s, ... max 40.96s
+			// (most requests have a 30s timeout by default at the Envoy level)
+			Buckets: prometheus.ExponentialBuckets(0.04, 2, 11),
+		},
+		[]string{"operation", "result"},
+	)
+
+	sendBatchSplitCount = promauto.NewHistogram(
+		prometheus.HistogramOpts{
+			Namespace: "gohbase",
+			Name:      "sendbatch_split_count",
+			Help:      "Count of Region Servers hit per SendBatch",
+			// 1, 2, 4, 8, 16, 32, 64, 128, 256, 512
+			Buckets: prometheus.ExponentialBuckets(1, 2, 10),
+		},
+	)
 )

rpc.go

@@ -239,6 +239,7 @@ func (c *client) SendBatch(ctx context.Context, batch []hrpc.Call) (
 	if !ok {
 		return res, false
 	}
+	sendBatchSplitCount.Observe(float64(len(rpcByClient)))
 
 	// Send each group of RPCs to region client to be executed.
 	type clientAndRPCs struct {