Merge #143876

143876: roachtest/tpccbench: fix double openmetrics emission r=csgourav a=sambhav-jain-16

`tpcc.NewResultWithSnapshots(warehouses, 0, snapshots)` appends the `snapshots` map with a value of the merged histogram for each key.
So when the test was exporting metrics into openmetrics, the result file would have double counts. This was resulting in wrong total values which calculating aggregated results.

This commit fixes the issue by moving `tpcc.NewResultWithSnapshots` to after conversion

Epic: none

Release note: None

Co-authored-by: Sambhav Jain <[email protected]>

Author: craig[bot]

pkg/cmd/roachtest/tests/tpcc.go

@@ -177,6 +177,25 @@ func getMaxWarehousesAboveEfficiency(
 	return aggregatedMetrics, nil
 }
 
+func convertSnapshotsToOpenmetrics(
+	ctx context.Context,
+	t test.Test,
+	c cluster.Cluster,
+	nodes option.NodeListOption,
+	warehouses int,
+	snapshots map[string][]exporter.SnapshotTick,
+) error {
+	statsFilePrefix := fmt.Sprintf("warehouses=%d/", warehouses)
+
+	// Create buffer for performance metrics
+	perfBuf := bytes.NewBuffer([]byte{})
+	exporter := roachtestutil.CreateWorkloadHistogramExporterWithLabels(t, c, map[string]string{warehouseLabel: fmt.Sprintf("%d", warehouses)})
+	writer := io.Writer(perfBuf)
+	exporter.Init(&writer)
+	defer roachtestutil.CloseExporter(ctx, exporter, t, c, perfBuf, nodes, statsFilePrefix)
+	return exportOpenMetrics(exporter, snapshots)
+}
+
 type tpccOptions struct {
 	DB                 string // database name
 	Warehouses         int
@@ -2051,26 +2070,17 @@ func runTPCCBench(ctx context.Context, t test.Test, c cluster.Cluster, b tpccBen
 					// overload but something that deserves failing the whole test.
 					t.Fatal(err)
 				}
-				result := tpcc.NewResultWithSnapshots(warehouses, 0, snapshots)
-
 				// This roachtest uses the stats.json emitted from hdr histogram to compute Tpmc and show it in the run log
 				// Since directly emitting openmetrics and computing Tpmc from it is not supported, it is better to convert the
 				// stats.json emitted to openmetrics in the test itself and upload it to the cluster
 				if t.ExportOpenmetrics() {
-					// Creating a prefix
-					statsFilePrefix := fmt.Sprintf("warehouses=%d/", warehouses)
-
-					// Create buffer for performance metrics
-					perfBuf := bytes.NewBuffer([]byte{})
-					exporter := roachtestutil.CreateWorkloadHistogramExporterWithLabels(t, c, map[string]string{warehouseLabel: fmt.Sprintf("%d", warehouses)})
-					writer := io.Writer(perfBuf)
-					exporter.Init(&writer)
-					defer roachtestutil.CloseExporter(ctx, exporter, t, c, perfBuf, group.LoadNodes, statsFilePrefix)
-
-					if err := exportOpenMetrics(exporter, snapshots); err != nil {
-						return errors.Wrapf(err, "error converting histogram to openmetrics")
+					if err = convertSnapshotsToOpenmetrics(ctx, t, c, group.LoadNodes, warehouses, snapshots); err != nil {
+						// If we are not able to convert, then there's an error
+						t.Fatal(err)
 					}
 				}
+
+				result := tpcc.NewResultWithSnapshots(warehouses, 0, snapshots)
 				resultChan <- result
 				return nil
 			})