[APM] Error rate on service list page is not in sync with the value at the transaction page

x-pack/plugins/apm/server/lib/transaction_groups/get_error_rate.ts

@@ -3,7 +3,7 @@
  * or more contributor license agreements. Licensed under the Elastic License;
  * you may not use this file except in compliance with the Elastic License.
  */
-import { mean } from 'lodash';
+import { AggregationResultOf } from '../../../typings/elasticsearch/aggregations';
 import { EventOutcome } from '../../../common/event_outcome';
 import {
   TRANSACTION_NAME,
@@ -52,6 +52,21 @@ export async function getErrorRate({
     ...esFilter,
   ];
 
+  const outcomes = {
+    terms: {
+      field: EVENT_OUTCOME,
+    },
+    aggs: {
+      count: {
+        value_count: {
+          field: getTransactionDurationFieldForAggregatedTransactions(
+            searchAggregatedTransactions
+          ),
+        },
+      },
+    },
+  };
+
   const params = {
     apm: {
       events: [
@@ -64,28 +79,16 @@ export async function getErrorRate({
       size: 0,
       query: { bool: { filter } },
       aggs: {
-        total_transactions: {
+        outcomes,
+        timeseries: {
           date_histogram: {
             field: '@timestamp',
             fixed_interval: getBucketSize(start, end).intervalString,
             min_doc_count: 0,
             extended_bounds: { min: start, max: end },
           },
           aggs: {
-            [EVENT_OUTCOME]: {
-              terms: {
-                field: EVENT_OUTCOME,
-              },
-              aggs: {
-                count: {
-                  value_count: {
-                    field: getTransactionDurationFieldForAggregatedTransactions(
-                      searchAggregatedTransactions
-                    ),
-                  },
-                },
-              },
-            },
+            outcomes,
           },
         },
       },
@@ -96,30 +99,36 @@ export async function getErrorRate({
 
   const noHits = resp.hits.total.value === 0;
 
-  const erroneousTransactionsRate =
-    resp.aggregations?.total_transactions.buckets.map((bucket) => {
-      const successful =
-        bucket[EVENT_OUTCOME].buckets.find(
-          (eventOutcomeBucket) =>
-            eventOutcomeBucket.key === EventOutcome.success
-        )?.count.value ?? 0;
+  if (!resp.aggregations) {
+    return { noHits, erroneousTransactionsRate: [], average: null };
+  }
 
-      const failed =
-        bucket[EVENT_OUTCOME].buckets.find(
-          (eventOutcomeBucket) =>
-            eventOutcomeBucket.key === EventOutcome.failure
-        )?.count.value ?? 0;
+  function calculateTransactionErrorPercentage(
+    outcomeResponse: AggregationResultOf<typeof outcomes, {}>
+  ) {
+    const successfulTransactions =
+      outcomeResponse.buckets.find(
+        (bucket) => bucket.key === EventOutcome.success
+      )?.count.value ?? 0;
+    const failedTransactions =
+      outcomeResponse.buckets.find(
+        (bucket) => bucket.key === EventOutcome.failure
+      )?.count.value ?? 0;
 
+    return failedTransactions / (successfulTransactions + failedTransactions);
+  }
+
+  const erroneousTransactionsRate = resp.aggregations.timeseries.buckets.map(
+    (bucket) => {
       return {
         x: bucket.key,
-        y: failed / (successful + failed),
+        y: calculateTransactionErrorPercentage(bucket.outcomes),
       };
-    }) || [];
+    }
+  );
 
-  const average = mean(
-    erroneousTransactionsRate
-      .map((errorRate) => errorRate.y)
-      .filter((y) => isFinite(y))
+  const average = calculateTransactionErrorPercentage(
+    resp.aggregations.outcomes
   );
 
   return { noHits, erroneousTransactionsRate, average };

x-pack/test/apm_api_integration/basic/tests/transaction_groups/error_rate.ts

@@ -80,7 +80,7 @@ export default function ApiTest({ getService }: FtrProviderContext) {
         });
 
         it('has the correct calculation for average', () => {
-          expectSnapshot(errorRateResponse.average).toMatchInline(`0.200076804915515`);
+          expectSnapshot(errorRateResponse.average).toMatchInline(`0.152173913043478`);
         });
 
         it('has the correct error rate', () => {