Replace stale metric that was being used for telemetry.

Signed-off-by: Harkishen-Singh <harkishensingh@hotmail.com>

In the previous commit, we added a common metric
promscale_query_duration_seconds{handler, type} to track duration of all
query based executions across all functions (and APIs when we implement for metrics)
hence the previous
promscale_trace_fetch_traces_api_execution_duration_seconds_bucket now
becomes trivial. This commit removes it and replaces it with the new
convention so that telemetry collection does not get affected with this
update.

pkg/jaeger/query/metrics.go

@@ -19,13 +19,9 @@ var (
 		Name:      "query_requests_executed_total",
 		Help:      "Total number of query requests successfully executed by /getTrace and /fetchTraces API.",
 	})
-	traceExecutionTime = prometheus.NewHistogram(prometheus.HistogramOpts{
-		Namespace: util.PromNamespace,
-		Subsystem: "trace",
-		Name:      "fetch_traces_api_execution_duration_seconds",
-		Help:      "Time taken by a trace query for complete execution in /fetchTraces API.",
-		Buckets:   []float64{0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10, 30, 50, 100, 250, 500, 1000, 2500},
-	})
+	// Even though this is handled by promscale_query_requests_total{subsystem="trace", handler="get_dependencies", code="200"}
+	// yet we will have to keep this metric for telemetry as extracting the underlying series from a metric will require
+	// changing telemetry arch that tracks the all prometheus metrics, just for this metric, which is not worth.
 	dependencyRequestsExec = prometheus.NewCounter(prometheus.CounterOpts{
 		Namespace: util.PromNamespace,
 		Subsystem: "trace",
@@ -48,7 +44,6 @@ func registerMetricsForTelemetry(t telemetry.Engine) error {
 func init() {
 	prometheus.MustRegister(
 		traceRequestsExec,
-		traceExecutionTime,
 		dependencyRequestsExec,
 	)
 }

pkg/jaeger/query/query.go

@@ -89,7 +89,6 @@ func (p *Query) FindTraces(ctx context.Context, query *spanstore.TraceQueryParam
 	res, err := findTraces(ctx, p.conn, query)
 	if err == nil {
 		metrics.RequestsTotal.With(prometheus.Labels{"subsystem": "trace", "handler": "find_traces", "code": "200"}).Inc()
-		traceExecutionTime.Observe(time.Since(start).Seconds())
 		traceRequestsExec.Add(1)
 		metrics.RequestsDuration.With(prometheus.Labels{"subsystem": "trace", "handler": "find_traces"}).Observe(time.Since(start).Seconds())
 	} else {

pkg/telemetry/promql.go

@@ -84,15 +84,15 @@ var promqlStats = []promqlTelemetry{
 		query: "histogram_quantile(0.99, sum by(le) (rate(promscale_metrics_query_remote_read_batch_duration_seconds_bucket[1h])))",
 	}, {
 		name:  "trace_query_execution_time_p50",
-		query: "histogram_quantile(0.5, sum by(le) (rate(promscale_trace_fetch_traces_api_execution_duration_seconds_bucket[1h])))",
+		query: `histogram_quantile(0.5, sum by(le) (rate(promscale_query_duration_seconds_bucket{handler="find_traces"}[1h])))`,
 	}, {
 		name:  "trace_query_execution_time_p90",
-		query: "histogram_quantile(0.9, sum by(le) (rate(promscale_trace_fetch_traces_api_execution_duration_seconds_bucket[1h])))",
+		query: `histogram_quantile(0.9, sum by(le) (rate(promscale_query_duration_seconds_bucket{handler="find_traces"}[1h])))`,
 	}, {
 		name:  "trace_query_execution_time_p95",
-		query: "histogram_quantile(0.95, sum by(le) (rate(promscale_trace_fetch_traces_api_execution_duration_seconds_bucket[1h])))",
+		query: `histogram_quantile(0.95, sum by(le) (rate(promscale_query_duration_seconds_bucket{handler="find_traces"}[1h])))`,
 	}, {
 		name:  "trace_query_execution_time_p99",
-		query: "histogram_quantile(0.99, sum by(le) (rate(promscale_trace_fetch_traces_api_execution_duration_seconds_bucket[1h])))",
+		query: `histogram_quantile(0.99, sum by(le) (rate(promscale_query_duration_seconds_bucket{handler="find_traces"}[1h])))`,
 	},
 }