From c9cbfc19b4c594de594d6eff008280ff225cfc5d Mon Sep 17 00:00:00 2001
From: Drew Davis <drew.davis@clickhouse.com>
Date: Mon, 10 Nov 2025 11:28:48 -0500
Subject: [PATCH 1/2] fix: Group alert histories by evaluation time

---
 .changeset/fair-berries-occur.md              |   6 +
 .../__tests__/alertHistory.test.ts            | 359 ++++++++++++++++++
 packages/api/src/controllers/alertHistory.ts  |  67 ++++
 packages/api/src/routers/api/alerts.ts        |  19 +-
 packages/app/src/AlertsPage.tsx               |   7 +-
 5 files changed, 439 insertions(+), 19 deletions(-)
 create mode 100644 .changeset/fair-berries-occur.md
 create mode 100644 packages/api/src/controllers/__tests__/alertHistory.test.ts
 create mode 100644 packages/api/src/controllers/alertHistory.ts

diff --git a/.changeset/fair-berries-occur.md b/.changeset/fair-berries-occur.md
new file mode 100644
index 000000000..8fb9e33db
--- /dev/null
+++ b/.changeset/fair-berries-occur.md
@@ -0,0 +1,6 @@
+---
+"@hyperdx/api": patch
+"@hyperdx/app": patch
+---
+
+fix: Group alert histories by evaluation time
diff --git a/packages/api/src/controllers/__tests__/alertHistory.test.ts b/packages/api/src/controllers/__tests__/alertHistory.test.ts
new file mode 100644
index 000000000..8d0922a00
--- /dev/null
+++ b/packages/api/src/controllers/__tests__/alertHistory.test.ts
@@ -0,0 +1,359 @@
+import { ObjectId } from 'mongodb';
+
+import { getRecentAlertHistories } from '@/controllers/alertHistory';
+import { clearDBCollections, closeDB, connectDB } from '@/fixtures';
+import Alert, { AlertState } from '@/models/alert';
+import AlertHistory from '@/models/alertHistory';
+import Team from '@/models/team';
+
+describe('alertHistory controller', () => {
+  beforeAll(async () => {
+    await connectDB();
+  });
+
+  afterEach(async () => {
+    await clearDBCollections();
+  });
+
+  afterAll(async () => {
+    await closeDB();
+  });
+
+  describe('getRecentAlertHistories', () => {
+    it('should return empty array when no histories exist', async () => {
+      const alertId = new ObjectId();
+      const histories = await getRecentAlertHistories({
+        alertId,
+        limit: 10,
+      });
+
+      expect(histories).toEqual([]);
+    });
+
+    it('should return recent alert histories for a given alert', async () => {
+      const team = await Team.create({ name: 'Test Team' });
+      const alert = await Alert.create({
+        team: team._id,
+        threshold: 100,
+        interval: '5m',
+        channel: { type: null },
+      });
+
+      const now = new Date('2024-01-15T12:00:00Z');
+      const earlier = new Date('2024-01-15T11:00:00Z');
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: now,
+        state: AlertState.ALERT,
+        counts: 5,
+        lastValues: [{ startTime: now, count: 5 }],
+      });
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: earlier,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: earlier, count: 0 }],
+      });
+
+      const histories = await getRecentAlertHistories({
+        alertId: new ObjectId(alert._id),
+        limit: 10,
+      });
+
+      expect(histories).toHaveLength(2);
+      expect(histories[0].createdAt).toEqual(now);
+      expect(histories[0].state).toBe(AlertState.ALERT);
+      expect(histories[0].counts).toBe(5);
+      expect(histories[1].createdAt).toEqual(earlier);
+      expect(histories[1].state).toBe(AlertState.OK);
+      expect(histories[1].counts).toBe(0);
+    });
+
+    it('should respect the limit parameter', async () => {
+      const team = await Team.create({ name: 'Test Team' });
+      const alert = await Alert.create({
+        team: team._id,
+        threshold: 100,
+        interval: '5m',
+        channel: { type: null },
+      });
+
+      // Create 5 histories
+      for (let i = 0; i < 5; i++) {
+        await AlertHistory.create({
+          alert: alert._id,
+          createdAt: new Date(Date.now() - i * 60000),
+          state: AlertState.OK,
+          counts: 0,
+          lastValues: [
+            { startTime: new Date(Date.now() - i * 60000), count: 0 },
+          ],
+        });
+      }
+
+      const histories = await getRecentAlertHistories({
+        alertId: new ObjectId(alert._id),
+        limit: 3,
+      });
+
+      expect(histories).toHaveLength(3);
+    });
+
+    it('should group histories by createdAt timestamp', async () => {
+      const team = await Team.create({ name: 'Test Team' });
+      const alert = await Alert.create({
+        team: team._id,
+        threshold: 100,
+        interval: '5m',
+        channel: { type: null },
+      });
+
+      const timestamp = new Date('2024-01-15T12:00:00Z');
+
+      // Create multiple histories with the same timestamp
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: timestamp,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: timestamp, count: 0 }],
+      });
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: timestamp,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: timestamp, count: 0 }],
+      });
+
+      const histories = await getRecentAlertHistories({
+        alertId: new ObjectId(alert._id),
+        limit: 10,
+      });
+
+      expect(histories).toHaveLength(1);
+      expect(histories[0].createdAt).toEqual(timestamp);
+      expect(histories[0].counts).toBe(0); // 0 + 0
+      expect(histories[0].lastValues).toHaveLength(2);
+    });
+
+    it('should set state to ALERT if any grouped history has ALERT state', async () => {
+      const team = await Team.create({ name: 'Test Team' });
+      const alert = await Alert.create({
+        team: team._id,
+        threshold: 100,
+        interval: '5m',
+        channel: { type: null },
+      });
+
+      const timestamp = new Date('2024-01-15T12:00:00Z');
+
+      // Create histories with mixed states at the same timestamp
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: timestamp,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: timestamp, count: 0 }],
+      });
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: timestamp,
+        state: AlertState.ALERT,
+        counts: 3,
+        lastValues: [{ startTime: timestamp, count: 3 }],
+      });
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: timestamp,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: timestamp, count: 0 }],
+      });
+
+      const histories = await getRecentAlertHistories({
+        alertId: new ObjectId(alert._id),
+        limit: 10,
+      });
+
+      expect(histories).toHaveLength(1);
+      expect(histories[0].state).toBe(AlertState.ALERT);
+      expect(histories[0].counts).toBe(3); // 0 + 3 + 0
+    });
+
+    it('should set state to OK when all grouped histories are OK', async () => {
+      const team = await Team.create({ name: 'Test Team' });
+      const alert = await Alert.create({
+        team: team._id,
+        threshold: 100,
+        interval: '5m',
+        channel: { type: null },
+      });
+
+      const timestamp = new Date('2024-01-15T12:00:00Z');
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: timestamp,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: timestamp, count: 0 }],
+      });
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: timestamp,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: timestamp, count: 0 }],
+      });
+
+      const histories = await getRecentAlertHistories({
+        alertId: new ObjectId(alert._id),
+        limit: 10,
+      });
+
+      expect(histories).toHaveLength(1);
+      expect(histories[0].state).toBe(AlertState.OK);
+    });
+
+    it('should sort histories by createdAt in descending order', async () => {
+      const team = await Team.create({ name: 'Test Team' });
+      const alert = await Alert.create({
+        team: team._id,
+        threshold: 100,
+        interval: '5m',
+        channel: { type: null },
+      });
+
+      const oldest = new Date('2024-01-15T10:00:00Z');
+      const middle = new Date('2024-01-15T11:00:00Z');
+      const newest = new Date('2024-01-15T12:00:00Z');
+
+      // Create in random order
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: middle,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: middle, count: 0 }],
+      });
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: newest,
+        state: AlertState.ALERT,
+        counts: 3,
+        lastValues: [{ startTime: newest, count: 3 }],
+      });
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: oldest,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: oldest, count: 0 }],
+      });
+
+      const histories = await getRecentAlertHistories({
+        alertId: new ObjectId(alert._id),
+        limit: 10,
+      });
+
+      expect(histories).toHaveLength(3);
+      expect(histories[0].createdAt).toEqual(newest);
+      expect(histories[1].createdAt).toEqual(middle);
+      expect(histories[2].createdAt).toEqual(oldest);
+    });
+
+    it('should sort lastValues by startTime in ascending order', async () => {
+      const team = await Team.create({ name: 'Test Team' });
+      const alert = await Alert.create({
+        team: team._id,
+        threshold: 100,
+        interval: '5m',
+        channel: { type: null },
+      });
+
+      const timestamp = new Date('2024-01-15T12:00:00Z');
+      const older = new Date('2024-01-15T11:00:00Z');
+      const newer = new Date('2024-01-15T13:00:00Z');
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: timestamp,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: older, count: 0 }],
+      });
+
+      await AlertHistory.create({
+        alert: alert._id,
+        createdAt: timestamp,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: newer, count: 0 }],
+      });
+
+      const histories = await getRecentAlertHistories({
+        alertId: new ObjectId(alert._id),
+        limit: 10,
+      });
+
+      expect(histories).toHaveLength(1);
+      expect(histories[0].lastValues).toHaveLength(2);
+      expect(histories[0].lastValues[0].startTime).toEqual(older);
+      expect(histories[0].lastValues[1].startTime).toEqual(newer);
+    });
+
+    it('should only return histories for the specified alert', async () => {
+      const team = await Team.create({ name: 'Test Team' });
+      const alert1 = await Alert.create({
+        team: team._id,
+        threshold: 100,
+        interval: '5m',
+        channel: { type: null },
+      });
+
+      const alert2 = await Alert.create({
+        team: team._id,
+        threshold: 200,
+        interval: '5m',
+        channel: { type: null },
+      });
+
+      const timestamp = new Date('2024-01-15T12:00:00Z');
+
+      await AlertHistory.create({
+        alert: alert1._id,
+        createdAt: timestamp,
+        state: AlertState.ALERT,
+        counts: 5,
+        lastValues: [{ startTime: timestamp, count: 5 }],
+      });
+
+      await AlertHistory.create({
+        alert: alert2._id,
+        createdAt: timestamp,
+        state: AlertState.OK,
+        counts: 0,
+        lastValues: [{ startTime: timestamp, count: 0 }],
+      });
+
+      const histories = await getRecentAlertHistories({
+        alertId: new ObjectId(alert1._id),
+        limit: 10,
+      });
+
+      expect(histories).toHaveLength(1);
+      expect(histories[0].state).toBe(AlertState.ALERT);
+      expect(histories[0].counts).toBe(5);
+    });
+  });
+});
diff --git a/packages/api/src/controllers/alertHistory.ts b/packages/api/src/controllers/alertHistory.ts
new file mode 100644
index 000000000..9b06ca262
--- /dev/null
+++ b/packages/api/src/controllers/alertHistory.ts
@@ -0,0 +1,67 @@
+import { ObjectId } from 'mongodb';
+
+import { AlertState } from '@/models/alert';
+import AlertHistory, { IAlertHistory } from '@/models/alertHistory';
+
+type GroupedAlertHistory = {
+  _id: Date;
+  states: string[];
+  counts: number;
+  lastValues: IAlertHistory['lastValues'][];
+};
+
+/**
+ * Gets the most recent alert histories for a given alert ID,
+ * limiting to the given number of entries.
+ */
+export async function getRecentAlertHistories({
+  alertId,
+  limit,
+}: {
+  alertId: ObjectId;
+  limit: number;
+}): Promise<Omit<IAlertHistory, 'alert'>[]> {
+  const groupedHistories = await AlertHistory.aggregate<GroupedAlertHistory>([
+    // Filter for the specific alert
+    {
+      $match: {
+        alert: new ObjectId(alertId),
+      },
+    },
+    // Group documents by createdAt
+    {
+      $group: {
+        _id: '$createdAt',
+        states: {
+          $push: '$state',
+        },
+        counts: {
+          $sum: '$counts',
+        },
+        lastValues: {
+          $push: '$lastValues',
+        },
+      },
+    },
+    // Take the `createdAtLimit` most recent groups
+    {
+      $sort: {
+        _id: -1,
+      },
+    },
+    {
+      $limit: limit,
+    },
+  ]);
+
+  return groupedHistories.map(group => ({
+    createdAt: group._id,
+    state: group.states.includes(AlertState.ALERT)
+      ? AlertState.ALERT
+      : AlertState.OK,
+    counts: group.counts,
+    lastValues: group.lastValues
+      .flat()
+      .sort((a, b) => a.startTime.getTime() - b.startTime.getTime()),
+  }));
+}
diff --git a/packages/api/src/routers/api/alerts.ts b/packages/api/src/routers/api/alerts.ts
index c3d8981ca..9c14fbbf8 100644
--- a/packages/api/src/routers/api/alerts.ts
+++ b/packages/api/src/routers/api/alerts.ts
@@ -1,8 +1,10 @@
 import express from 'express';
 import _ from 'lodash';
+import { ObjectId } from 'mongodb';
 import { z } from 'zod';
 import { validateRequest } from 'zod-express-middleware';
 
+import { getRecentAlertHistories } from '@/controllers/alertHistory';
 import {
   createAlert,
   deleteAlert,
@@ -10,7 +12,6 @@ import {
   getAlertsEnhanced,
   updateAlert,
 } from '@/controllers/alerts';
-import AlertHistory from '@/models/alertHistory';
 import { alertSchema, objectIdSchema } from '@/utils/zod';
 
 const router = express.Router();
@@ -26,18 +27,10 @@ router.get('/', async (req, res, next) => {
 
     const data = await Promise.all(
       alerts.map(async alert => {
-        const history = await AlertHistory.find(
-          {
-            alert: alert._id,
-          },
-          {
-            __v: 0,
-            _id: 0,
-            alert: 0,
-          },
-        )
-          .sort({ createdAt: -1 })
-          .limit(20);
+        const history = await getRecentAlertHistories({
+          alertId: new ObjectId(alert._id),
+          limit: 20,
+        });
 
         return {
           history,
diff --git a/packages/app/src/AlertsPage.tsx b/packages/app/src/AlertsPage.tsx
index 808f88567..f6c197f11 100644
--- a/packages/app/src/AlertsPage.tsx
+++ b/packages/app/src/AlertsPage.tsx
@@ -18,18 +18,13 @@ import type { AlertsPageItem } from './types';
 
 import styles from '../styles/AlertsPage.module.scss';
 
-// TODO: exceptions latestHighestValue needs to be different condition (total count of exceptions not highest value within an exception)
-
 function AlertHistoryCard({ history }: { history: AlertHistory }) {
   const start = new Date(history.createdAt.toString());
   const today = React.useMemo(() => new Date(), []);
-  const latestHighestValue = history.lastValues.length
-    ? Math.max(...history.lastValues.map(({ count }) => count))
-    : 0;
 
   return (
     <Tooltip
-      label={latestHighestValue + ' ' + formatRelative(start, today)}
+      label={`${history.counts ?? 0} alerts at ${formatRelative(start, today)}`}
       color="dark"
       withArrow
     >

From 68a9fa3cb5f9c212765bbedecefe90e777a80a82 Mon Sep 17 00:00:00 2001
From: Drew Davis <drew.davis@clickhouse.com>
Date: Mon, 10 Nov 2025 12:16:19 -0500
Subject: [PATCH 2/2] style: Remove extra 'at' in AlertCard

---
 packages/app/src/AlertsPage.tsx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/app/src/AlertsPage.tsx b/packages/app/src/AlertsPage.tsx
index f6c197f11..cf1054904 100644
--- a/packages/app/src/AlertsPage.tsx
+++ b/packages/app/src/AlertsPage.tsx
@@ -24,7 +24,7 @@ function AlertHistoryCard({ history }: { history: AlertHistory }) {
 
   return (
     <Tooltip
-      label={`${history.counts ?? 0} alerts at ${formatRelative(start, today)}`}
+      label={`${history.counts ?? 0} alerts ${formatRelative(start, today)}`}
       color="dark"
       withArrow
     >