wip

packages/db/src/buffers/event-buffer.test.ts

@@ -10,7 +10,11 @@ import { EventBuffer } from './event-buffer';
 const redis = getRedisCache();
 
 beforeEach(async () => {
-  await redis.flushdb();
+  const keys = [
+    ...await redis.keys('event*'),
+    ...await redis.keys('live:*'),
+  ];
+  if (keys.length > 0) await redis.del(...keys);
 });
 
 afterAll(async () => {
@@ -273,4 +277,24 @@ describe('EventBuffer', () => {
 
     expect(await eventBuffer.getBufferSize()).toBe(5);
   });
+
+  it('retains events in queue when ClickHouse insert fails', async () => {
+    eventBuffer.add({
+      project_id: 'p12',
+      name: 'event1',
+      created_at: new Date().toISOString(),
+    } as any);
+    await eventBuffer.flush();
+
+    const insertSpy = vi
+      .spyOn(ch, 'insert')
+      .mockRejectedValueOnce(new Error('ClickHouse unavailable'));
+
+    await eventBuffer.processBuffer();
+
+    // Events must still be in the queue — not lost
+    expect(await eventBuffer.getBufferSize()).toBe(1);
+
+    insertSpy.mockRestore();
+  });
 });

packages/db/src/buffers/profile-buffer.test.ts

@@ -1,6 +1,5 @@
 import { getRedisCache } from '@openpanel/redis';
 import { afterAll, beforeEach, describe, expect, it, vi } from 'vitest';
-import { getSafeJson } from '@openpanel/json';
 import type { IClickhouseProfile } from '../services/profile.service';
 
 // Mock chQuery to avoid hitting real ClickHouse
@@ -36,7 +35,11 @@ function makeProfile(overrides: Partial<IClickhouseProfile>): IClickhouseProfile
 }
 
 beforeEach(async () => {
-  await redis.flushdb();
+  const keys = [
+    ...await redis.keys('profile*'),
+    ...await redis.keys('lock:profile'),
+  ];
+  if (keys.length > 0) await redis.del(...keys);
   vi.mocked(chQuery).mockResolvedValue([]);
 });
 
@@ -63,64 +66,12 @@ describe('ProfileBuffer', () => {
     expect(sizeAfter).toBe(sizeBefore + 1);
   });
 
-  it('merges subsequent updates via cache (sequential calls)', async () => {
+  it('concurrent adds: both raw profiles are queued', async () => {
     const identifyProfile = makeProfile({
       first_name: 'John',
       email: 'john@example.com',
       groups: [],
     });
-
-    const groupProfile = makeProfile({
-      first_name: '',
-      email: '',
-      groups: ['group-abc'],
-    });
-
-    // Sequential: identify first, then group
-    await profileBuffer.add(identifyProfile);
-    await profileBuffer.add(groupProfile);
-
-    // Second add should read the cached identify profile and merge groups in
-    const cached = await profileBuffer.fetchFromCache('profile-1', 'project-1');
-    expect(cached?.first_name).toBe('John');
-    expect(cached?.email).toBe('john@example.com');
-    expect(cached?.groups).toContain('group-abc');
-  });
-
-  it('race condition: concurrent identify + group calls preserve all data', async () => {
-    const identifyProfile = makeProfile({
-      first_name: 'John',
-      email: 'john@example.com',
-      groups: [],
-    });
-
-    const groupProfile = makeProfile({
-      first_name: '',
-      email: '',
-      groups: ['group-abc'],
-    });
-
-    // Both calls run concurrently — the per-profile lock serializes them so the
-    // second one reads the first's result from cache and merges correctly.
-    await Promise.all([
-      profileBuffer.add(identifyProfile),
-      profileBuffer.add(groupProfile),
-    ]);
-
-    const cached = await profileBuffer.fetchFromCache('profile-1', 'project-1');
-
-    expect(cached?.first_name).toBe('John');
-    expect(cached?.email).toBe('john@example.com');
-    expect(cached?.groups).toContain('group-abc');
-  });
-
-  it('race condition: concurrent writes produce one merged buffer entry', async () => {
-    const identifyProfile = makeProfile({
-      first_name: 'John',
-      email: 'john@example.com',
-      groups: [],
-    });
-
     const groupProfile = makeProfile({
       first_name: '',
       email: '',
@@ -128,24 +79,126 @@ describe('ProfileBuffer', () => {
     });
 
     const sizeBefore = await profileBuffer.getBufferSize();
+    await Promise.all([
+      profileBuffer.add(identifyProfile),
+      profileBuffer.add(groupProfile),
+    ]);
+    const sizeAfter = await profileBuffer.getBufferSize();
+
+    // Both raw profiles are queued; merge happens at flush time
+    expect(sizeAfter).toBe(sizeBefore + 2);
+  });
+
+  it('merges sequential updates for the same profile at flush time', async () => {
+    const identifyProfile = makeProfile({
+      first_name: 'John',
+      email: 'john@example.com',
+      groups: [],
+    });
+    const groupProfile = makeProfile({
+      first_name: '',
+      email: '',
+      groups: ['group-abc'],
+    });
+
+    await profileBuffer.add(identifyProfile);
+    await profileBuffer.add(groupProfile);
+    await profileBuffer.processBuffer();
+
+    const cached = await profileBuffer.fetchFromCache('profile-1', 'project-1');
+    expect(cached?.first_name).toBe('John');
+    expect(cached?.email).toBe('john@example.com');
+    expect(cached?.groups).toContain('group-abc');
+  });
+
+  it('merges concurrent updates for the same profile at flush time', async () => {
+    const identifyProfile = makeProfile({
+      first_name: 'John',
+      email: 'john@example.com',
+      groups: [],
+    });
+    const groupProfile = makeProfile({
+      first_name: '',
+      email: '',
+      groups: ['group-abc'],
+    });
 
     await Promise.all([
       profileBuffer.add(identifyProfile),
       profileBuffer.add(groupProfile),
     ]);
+    await profileBuffer.processBuffer();
 
-    const sizeAfter = await profileBuffer.getBufferSize();
+    const cached = await profileBuffer.fetchFromCache('profile-1', 'project-1');
+    expect(cached?.first_name).toBe('John');
+    expect(cached?.email).toBe('john@example.com');
+    expect(cached?.groups).toContain('group-abc');
+  });
 
-    // The second add merges into the first — only 2 buffer entries total
-    // (one from identify, one merged update with group)
-    expect(sizeAfter).toBe(sizeBefore + 2);
+  it('uses existing ClickHouse data for cache misses when merging', async () => {
+    const existingInClickhouse = makeProfile({
+      first_name: 'Jane',
+      email: 'jane@example.com',
+      groups: ['existing-group'],
+    });
+    vi.mocked(chQuery).mockResolvedValue([existingInClickhouse]);
 
-    // The last entry in the buffer should have both name and group
-    const rawEntries = await redis.lrange('profile-buffer', 0, -1);
-    const entries = rawEntries.map((e) => getSafeJson<IClickhouseProfile>(e));
-    const lastEntry = entries[entries.length - 1];
+    const incomingProfile = makeProfile({
+      first_name: '',
+      email: '',
+      groups: ['new-group'],
+    });
 
-    expect(lastEntry?.first_name).toBe('John');
-    expect(lastEntry?.groups).toContain('group-abc');
+    await profileBuffer.add(incomingProfile);
+    await profileBuffer.processBuffer();
+
+    const cached = await profileBuffer.fetchFromCache('profile-1', 'project-1');
+    expect(cached?.first_name).toBe('Jane');
+    expect(cached?.email).toBe('jane@example.com');
+    expect(cached?.groups).toContain('existing-group');
+    expect(cached?.groups).toContain('new-group');
+  });
+
+  it('buffer is empty after flush', async () => {
+    await profileBuffer.add(makeProfile({ first_name: 'John' }));
+    expect(await profileBuffer.getBufferSize()).toBe(1);
+
+    await profileBuffer.processBuffer();
+
+    expect(await profileBuffer.getBufferSize()).toBe(0);
+  });
+
+  it('retains profiles in queue when ClickHouse insert fails', async () => {
+    await profileBuffer.add(makeProfile({ first_name: 'John' }));
+
+    const { ch } = await import('../clickhouse/client');
+    const insertSpy = vi
+      .spyOn(ch, 'insert')
+      .mockRejectedValueOnce(new Error('ClickHouse unavailable'));
+
+    await profileBuffer.processBuffer();
+
+    // Profiles must still be in the queue — not lost
+    expect(await profileBuffer.getBufferSize()).toBe(1);
+
+    insertSpy.mockRestore();
+  });
+
+  it('proceeds with insert when ClickHouse fetch fails (treats profiles as new)', async () => {
+    vi.mocked(chQuery).mockRejectedValueOnce(new Error('ClickHouse unavailable'));
+
+    const { ch } = await import('../clickhouse/client');
+    const insertSpy = vi
+      .spyOn(ch, 'insert')
+      .mockResolvedValueOnce(undefined as any);
+
+    await profileBuffer.add(makeProfile({ first_name: 'John' }));
+    await profileBuffer.processBuffer();
+
+    // Insert must still have been called — no data loss even when fetch fails
+    expect(insertSpy).toHaveBeenCalled();
+    expect(await profileBuffer.getBufferSize()).toBe(0);
+
+    insertSpy.mockRestore();
   });
 });

packages/db/src/buffers/profile-buffer.ts

@@ -1,9 +1,6 @@
 import { deepMergeObjects } from '@openpanel/common';
-import { generateSecureId } from '@openpanel/common/server';
 import { getSafeJson } from '@openpanel/json';
-import type { ILogger } from '@openpanel/logger';
 import { getRedisCache, type Redis } from '@openpanel/redis';
-import shallowEqual from 'fast-deep-equal';
 import { omit, uniq } from 'ramda';
 import sqlstring from 'sqlstring';
 import { ch, chQuery, TABLE_NAMES } from '../clickhouse/client';
@@ -11,29 +8,24 @@ import type { IClickhouseProfile } from '../services/profile.service';
 import { BaseBuffer } from './base-buffer';
 
 export class ProfileBuffer extends BaseBuffer {
-  private batchSize = process.env.PROFILE_BUFFER_BATCH_SIZE
+  private readonly batchSize = process.env.PROFILE_BUFFER_BATCH_SIZE
     ? Number.parseInt(process.env.PROFILE_BUFFER_BATCH_SIZE, 10)
     : 200;
-  private chunkSize = process.env.PROFILE_BUFFER_CHUNK_SIZE
+  private readonly chunkSize = process.env.PROFILE_BUFFER_CHUNK_SIZE
     ? Number.parseInt(process.env.PROFILE_BUFFER_CHUNK_SIZE, 10)
     : 1000;
-  private ttlInSeconds = process.env.PROFILE_BUFFER_TTL_IN_SECONDS
+  private readonly ttlInSeconds = process.env.PROFILE_BUFFER_TTL_IN_SECONDS
     ? Number.parseInt(process.env.PROFILE_BUFFER_TTL_IN_SECONDS, 10)
     : 60 * 60;
+  /** Max profiles per ClickHouse IN-clause fetch to keep query size bounded */
+  private readonly fetchChunkSize = process.env.PROFILE_BUFFER_FETCH_CHUNK_SIZE
+    ? Number.parseInt(process.env.PROFILE_BUFFER_FETCH_CHUNK_SIZE, 10)
+    : 50;
 
   private readonly redisKey = 'profile-buffer';
   private readonly redisProfilePrefix = 'profile-cache:';
 
-  private redis: Redis;
-  private releaseLockSha: string | null = null;
-
-  private readonly releaseLockScript = `
-    if redis.call("get", KEYS[1]) == ARGV[1] then
-      return redis.call("del", KEYS[1])
-    else
-      return 0
-    end
-  `;
+  private readonly redis: Redis;
 
   constructor() {
     super({
@@ -43,9 +35,6 @@ export class ProfileBuffer extends BaseBuffer {
       },
     });
     this.redis = getRedisCache();
-    this.redis.script('LOAD', this.releaseLockScript).then((sha) => {
-      this.releaseLockSha = sha as string;
-    });
   }
 
   private getProfileCacheKey({
@@ -58,243 +47,226 @@ export class ProfileBuffer extends BaseBuffer {
     return `${this.redisProfilePrefix}${projectId}:${profileId}`;
   }
 
-  private async withProfileLock<T>(
+  public async fetchFromCache(
     profileId: string,
-    projectId: string,
-    fn: () => Promise<T>
-  ): Promise<T> {
-    const lockKey = `profile-lock:${projectId}:${profileId}`;
-    const lockId = generateSecureId('lock');
-    const maxRetries = 20;
-    const retryDelayMs = 50;
-
-    for (let i = 0; i < maxRetries; i++) {
-      const acquired = await this.redis.set(lockKey, lockId, 'EX', 5, 'NX');
-      if (acquired === 'OK') {
-        try {
-          return await fn();
-        } finally {
-          if (this.releaseLockSha) {
-            await this.redis.evalsha(this.releaseLockSha, 1, lockKey, lockId);
-          } else {
-            await this.redis.eval(this.releaseLockScript, 1, lockKey, lockId);
-          }
-        }
-      }
-      await new Promise((resolve) => setTimeout(resolve, retryDelayMs));
+    projectId: string
+  ): Promise<IClickhouseProfile | null> {
+    const cacheKey = this.getProfileCacheKey({ profileId, projectId });
+    const cached = await this.redis.get(cacheKey);
+    if (!cached) {
+      return null;
     }
-
-    this.logger.error(
-      'Failed to acquire profile lock, proceeding without lock',
-      {
-        profileId,
-        projectId,
-      }
-    );
-    return fn();
+    return getSafeJson<IClickhouseProfile>(cached);
   }
 
-  async alreadyExists(profile: IClickhouseProfile) {
-    const cacheKey = this.getProfileCacheKey({
-      profileId: profile.id,
-      projectId: profile.project_id,
-    });
-    return (await this.redis.exists(cacheKey)) === 1;
-  }
-
-  async add(profile: IClickhouseProfile, isFromEvent = false) {
-    const logger = this.logger.child({
-      projectId: profile.project_id,
-      profileId: profile.id,
-    });
-
+  async add(profile: IClickhouseProfile, _isFromEvent = false) {
     try {
-      logger.debug('Adding profile');
+      const result = await this.redis
+        .multi()
+        .rpush(this.redisKey, JSON.stringify(profile))
+        .incr(this.bufferCounterKey)
+        .llen(this.redisKey)
+        .exec();
 
-      if (isFromEvent && (await this.alreadyExists(profile))) {
-        logger.debug('Profile already created, skipping');
+      if (!result) {
+        this.logger.error('Failed to add profile to Redis', { profile });
         return;
       }
 
-      await this.withProfileLock(profile.id, profile.project_id, async () => {
-        const existingProfile = await this.fetchProfile(profile, logger);
-
-        // Delete any properties that are not server related if we have a non-server profile
-        if (
-          existingProfile?.properties.device !== 'server' &&
-          profile.properties.device === 'server'
-        ) {
-          profile.properties = omit(
-            [
-              'city',
-              'country',
-              'region',
-              'longitude',
-              'latitude',
-              'os',
-              'osVersion',
-              'browser',
-              'device',
-              'isServer',
-              'os_version',
-              'browser_version',
-            ],
-            profile.properties
-          );
-        }
-
-        const mergedProfile: IClickhouseProfile = existingProfile
-          ? {
-              ...deepMergeObjects(
-                existingProfile,
-                omit(['created_at', 'groups'], profile)
-              ),
-              groups: uniq([
-                ...(existingProfile.groups ?? []),
-                ...(profile.groups ?? []),
-              ]),
-            }
-          : profile;
-
-        if (
-          profile &&
-          existingProfile &&
-          shallowEqual(
-            omit(['created_at'], existingProfile),
-            omit(['created_at'], mergedProfile)
-          )
-        ) {
-          this.logger.debug('Profile not changed, skipping');
-          return;
-        }
-
-        this.logger.debug('Merged profile will be inserted', {
-          mergedProfile,
-          existingProfile,
-          profile,
-        });
-
-        const cacheKey = this.getProfileCacheKey({
-          profileId: profile.id,
-          projectId: profile.project_id,
-        });
-
-        const result = await this.redis
-          .multi()
-          .set(cacheKey, JSON.stringify(mergedProfile), 'EX', this.ttlInSeconds)
-          .rpush(this.redisKey, JSON.stringify(mergedProfile))
-          .incr(this.bufferCounterKey)
-          .llen(this.redisKey)
-          .exec();
-
-        if (!result) {
-          this.logger.error('Failed to add profile to Redis', {
-            profile,
-            cacheKey,
-          });
-          return;
-        }
-        const bufferLength = (result?.[3]?.[1] as number) ?? 0;
-
-        this.logger.debug('Current buffer length', {
-          bufferLength,
-          batchSize: this.batchSize,
-        });
-        if (bufferLength >= this.batchSize) {
-          await this.tryFlush();
-        }
-      });
+      const bufferLength = (result?.[2]?.[1] as number) ?? 0;
+      if (bufferLength >= this.batchSize) {
+        await this.tryFlush();
+      }
     } catch (error) {
       this.logger.error('Failed to add profile', { error, profile });
     }
   }
 
-  private async fetchProfile(
-    profile: IClickhouseProfile,
-    logger: ILogger
-  ): Promise<IClickhouseProfile | null> {
-    const existingProfile = await this.fetchFromCache(
-      profile.id,
-      profile.project_id
-    );
-    if (existingProfile) {
-      logger.debug('Profile found in Redis');
-      return existingProfile;
+  private mergeProfiles(
+    existing: IClickhouseProfile | null,
+    incoming: IClickhouseProfile
+  ): IClickhouseProfile {
+    if (!existing) {
+      return incoming;
     }
 
-    return this.fetchFromClickhouse(profile, logger);
-  }
-
-  public async fetchFromCache(
-    profileId: string,
-    projectId: string
-  ): Promise<IClickhouseProfile | null> {
-    const cacheKey = this.getProfileCacheKey({
-      profileId,
-      projectId,
-    });
-    const existingProfile = await this.redis.get(cacheKey);
-    if (!existingProfile) {
-      return null;
+    let profile = incoming;
+    if (
+      existing.properties.device !== 'server' &&
+      incoming.properties.device === 'server'
+    ) {
+      profile = {
+        ...incoming,
+        properties: omit(
+          [
+            'city',
+            'country',
+            'region',
+            'longitude',
+            'latitude',
+            'os',
+            'osVersion',
+            'browser',
+            'device',
+            'isServer',
+            'os_version',
+            'browser_version',
+          ],
+          incoming.properties
+        ),
+      };
     }
-    return getSafeJson<IClickhouseProfile>(existingProfile);
+
+    return {
+      ...deepMergeObjects(existing, omit(['created_at', 'groups'], profile)),
+      groups: uniq([...(existing.groups ?? []), ...(incoming.groups ?? [])]),
+    };
   }
 
-  private async fetchFromClickhouse(
-    profile: IClickhouseProfile,
-    logger: ILogger
-  ): Promise<IClickhouseProfile | null> {
-    logger.debug('Fetching profile from Clickhouse');
-    const result = await chQuery<IClickhouseProfile>(
-      `SELECT 
-        id, 
-        project_id,
-        last_value(nullIf(first_name, '')) as first_name, 
-        last_value(nullIf(last_name, '')) as last_name, 
-        last_value(nullIf(email, '')) as email, 
-        last_value(nullIf(avatar, '')) as avatar, 
-        last_value(is_external) as is_external, 
-        last_value(properties) as properties, 
-        last_value(created_at) as created_at
-      FROM ${TABLE_NAMES.profiles} 
-      WHERE 
-        id = ${sqlstring.escape(String(profile.id))} AND 
-        project_id = ${sqlstring.escape(profile.project_id)}
-        ${
-          profile.is_external === false
-            ? ' AND profiles.created_at > now() - INTERVAL 2 DAY'
-            : ''
+  private async batchFetchFromClickhouse(
+    profiles: IClickhouseProfile[]
+  ): Promise<Map<string, IClickhouseProfile>> {
+    const result = new Map<string, IClickhouseProfile>();
+
+    // Non-external (anonymous/device) profiles get a 2-day recency filter to
+    // avoid pulling stale anonymous sessions from far back.
+    const external = profiles.filter((p) => p.is_external !== false);
+    const nonExternal = profiles.filter((p) => p.is_external === false);
+
+    const fetchGroup = async (
+      group: IClickhouseProfile[],
+      withDateFilter: boolean
+    ) => {
+      for (const chunk of this.chunks(group, this.fetchChunkSize)) {
+        const tuples = chunk
+          .map(
+            (p) =>
+              `(${sqlstring.escape(String(p.id))}, ${sqlstring.escape(p.project_id)})`
+          )
+          .join(', ');
+        try {
+          const rows = await chQuery<IClickhouseProfile>(
+            `SELECT
+              id,
+              project_id,
+              last_value(nullIf(first_name, '')) as first_name,
+              last_value(nullIf(last_name, '')) as last_name,
+              last_value(nullIf(email, '')) as email,
+              last_value(nullIf(avatar, '')) as avatar,
+              last_value(is_external) as is_external,
+              last_value(properties) as properties,
+              last_value(created_at) as created_at
+            FROM ${TABLE_NAMES.profiles}
+            WHERE (id, project_id) IN (${tuples})
+            ${withDateFilter ? 'AND created_at > now() - INTERVAL 2 DAY' : ''}
+            GROUP BY id, project_id
+            ORDER BY created_at DESC`
+          );
+          for (const row of rows) {
+            result.set(`${row.project_id}:${row.id}`, row);
+          }
+        } catch (error) {
+          this.logger.warn(
+            'Failed to batch fetch profiles from Clickhouse, proceeding without existing data',
+            { error, chunkSize: chunk.length }
+          );
         }
-      GROUP BY id, project_id 
-      ORDER BY created_at DESC 
-      LIMIT 1`
-    );
-    logger.debug('Clickhouse fetch result', {
-      found: !!result[0],
-    });
-    return result[0] || null;
+      }
+    };
+
+    await Promise.all([
+      fetchGroup(external, false),
+      fetchGroup(nonExternal, true),
+    ]);
+
+    return result;
   }
 
   async processBuffer() {
     try {
       this.logger.debug('Starting profile buffer processing');
-      const profiles = await this.redis.lrange(
+      const rawProfiles = await this.redis.lrange(
         this.redisKey,
         0,
         this.batchSize - 1
       );
 
-      if (profiles.length === 0) {
+      if (rawProfiles.length === 0) {
         this.logger.debug('No profiles to process');
         return;
       }
 
-      this.logger.debug(`Processing ${profiles.length} profiles in buffer`);
-      const parsedProfiles = profiles.map((p) =>
-        getSafeJson<IClickhouseProfile>(p)
-      );
+      const parsedProfiles = rawProfiles
+        .map((p) => getSafeJson<IClickhouseProfile>(p))
+        .filter(Boolean) as IClickhouseProfile[];
 
-      for (const chunk of this.chunks(parsedProfiles, this.chunkSize)) {
+      // Merge within batch: collapse multiple updates for the same profile
+      const mergedInBatch = new Map<string, IClickhouseProfile>();
+      for (const profile of parsedProfiles) {
+        const key = `${profile.project_id}:${profile.id}`;
+        mergedInBatch.set(
+          key,
+          this.mergeProfiles(mergedInBatch.get(key) ?? null, profile)
+        );
+      }
+
+      const uniqueProfiles = Array.from(mergedInBatch.values());
+
+      // Check Redis cache for all unique profiles in a single MGET
+      const cacheKeys = uniqueProfiles.map((p) =>
+        this.getProfileCacheKey({ profileId: p.id, projectId: p.project_id })
+      );
+      const cacheResults = await this.redis.mget(...cacheKeys);
+
+      const existingByKey = new Map<string, IClickhouseProfile>();
+      const cacheMisses: IClickhouseProfile[] = [];
+      for (let i = 0; i < uniqueProfiles.length; i++) {
+        const uniqueProfile = uniqueProfiles[i];
+        if (uniqueProfile) {
+          const key = `${uniqueProfile.project_id}:${uniqueProfile.id}`;
+          const cached = cacheResults[i]
+            ? getSafeJson<IClickhouseProfile>(cacheResults[i]!)
+            : null;
+          if (cached) {
+            existingByKey.set(key, cached);
+          } else {
+            cacheMisses.push(uniqueProfile);
+          }
+        }
+      }
+
+      // Fetch cache misses from ClickHouse in bounded chunks
+      if (cacheMisses.length > 0) {
+        const clickhouseResults =
+          await this.batchFetchFromClickhouse(cacheMisses);
+        for (const [key, profile] of clickhouseResults) {
+          existingByKey.set(key, profile);
+        }
+      }
+
+      // Final merge: in-batch profile + existing (from cache or ClickHouse)
+      const toInsert: IClickhouseProfile[] = [];
+      const multi = this.redis.multi();
+
+      for (const profile of uniqueProfiles) {
+        const key = `${profile.project_id}:${profile.id}`;
+        const merged = this.mergeProfiles(
+          existingByKey.get(key) ?? null,
+          profile
+        );
+        toInsert.push(merged);
+        multi.set(
+          this.getProfileCacheKey({
+            projectId: profile.project_id,
+            profileId: profile.id,
+          }),
+          JSON.stringify(merged),
+          'EX',
+          this.ttlInSeconds
+        );
+      }
+
+      for (const chunk of this.chunks(toInsert, this.chunkSize)) {
         await ch.insert({
           table: TABLE_NAMES.profiles,
           values: chunk,
@@ -302,22 +274,21 @@ export class ProfileBuffer extends BaseBuffer {
         });
       }
 
-      // Only remove profiles after successful insert and update counter
-      await this.redis
-        .multi()
-        .ltrim(this.redisKey, profiles.length, -1)
-        .decrby(this.bufferCounterKey, profiles.length)
-        .exec();
+      multi
+        .ltrim(this.redisKey, rawProfiles.length, -1)
+        .decrby(this.bufferCounterKey, rawProfiles.length);
+      await multi.exec();
 
       this.logger.debug('Successfully completed profile processing', {
-        totalProfiles: profiles.length,
+        totalProfiles: rawProfiles.length,
+        uniqueProfiles: uniqueProfiles.length,
       });
     } catch (error) {
       this.logger.error('Failed to process buffer', { error });
     }
   }
 
-  async getBufferSize() {
+  getBufferSize() {
     return this.getBufferSizeWithCounter(() => this.redis.llen(this.redisKey));
   }
 }

packages/db/src/buffers/session-buffer.test.ts

@@ -0,0 +1,122 @@
+import { getRedisCache } from '@openpanel/redis';
+import { afterAll, beforeEach, describe, expect, it, vi } from 'vitest';
+import { ch } from '../clickhouse/client';
+
+vi.mock('../clickhouse/client', () => ({
+  ch: {
+    insert: vi.fn().mockResolvedValue(undefined),
+  },
+  TABLE_NAMES: {
+    sessions: 'sessions',
+  },
+}));
+
+import { SessionBuffer } from './session-buffer';
+import type { IClickhouseEvent } from '../services/event.service';
+
+const redis = getRedisCache();
+
+function makeEvent(overrides: Partial<IClickhouseEvent>): IClickhouseEvent {
+  return {
+    id: 'event-1',
+    project_id: 'project-1',
+    profile_id: 'profile-1',
+    device_id: 'device-1',
+    session_id: 'session-1',
+    name: 'screen_view',
+    path: '/home',
+    origin: '',
+    referrer: '',
+    referrer_name: '',
+    referrer_type: '',
+    duration: 0,
+    properties: {},
+    created_at: new Date().toISOString(),
+    groups: [],
+    ...overrides,
+  } as IClickhouseEvent;
+}
+
+beforeEach(async () => {
+  const keys = [
+    ...await redis.keys('session*'),
+    ...await redis.keys('lock:session'),
+  ];
+  if (keys.length > 0) await redis.del(...keys);
+  vi.mocked(ch.insert).mockResolvedValue(undefined as any);
+});
+
+afterAll(async () => {
+  try {
+    await redis.quit();
+  } catch {}
+});
+
+describe('SessionBuffer', () => {
+  let sessionBuffer: SessionBuffer;
+
+  beforeEach(() => {
+    sessionBuffer = new SessionBuffer();
+  });
+
+  it('adds a new session to the buffer', async () => {
+    const sizeBefore = await sessionBuffer.getBufferSize();
+    await sessionBuffer.add(makeEvent({}));
+    const sizeAfter = await sessionBuffer.getBufferSize();
+
+    expect(sizeAfter).toBe(sizeBefore + 1);
+  });
+
+  it('skips session_start and session_end events', async () => {
+    const sizeBefore = await sessionBuffer.getBufferSize();
+    await sessionBuffer.add(makeEvent({ name: 'session_start' }));
+    await sessionBuffer.add(makeEvent({ name: 'session_end' }));
+    const sizeAfter = await sessionBuffer.getBufferSize();
+
+    expect(sizeAfter).toBe(sizeBefore);
+  });
+
+  it('updates existing session on subsequent events', async () => {
+    const t0 = Date.now();
+    await sessionBuffer.add(makeEvent({ created_at: new Date(t0).toISOString() }));
+
+    // Second event updates the same session — emits old (sign=-1) + new (sign=1)
+    const sizeBefore = await sessionBuffer.getBufferSize();
+    await sessionBuffer.add(makeEvent({ created_at: new Date(t0 + 5000).toISOString() }));
+    const sizeAfter = await sessionBuffer.getBufferSize();
+
+    expect(sizeAfter).toBe(sizeBefore + 2);
+  });
+
+  it('processes buffer and inserts sessions into ClickHouse', async () => {
+    await sessionBuffer.add(makeEvent({}));
+
+    const insertSpy = vi
+      .spyOn(ch, 'insert')
+      .mockResolvedValueOnce(undefined as any);
+
+    await sessionBuffer.processBuffer();
+
+    expect(insertSpy).toHaveBeenCalledWith(
+      expect.objectContaining({ table: 'sessions', format: 'JSONEachRow' })
+    );
+    expect(await sessionBuffer.getBufferSize()).toBe(0);
+
+    insertSpy.mockRestore();
+  });
+
+  it('retains sessions in queue when ClickHouse insert fails', async () => {
+    await sessionBuffer.add(makeEvent({}));
+
+    const insertSpy = vi
+      .spyOn(ch, 'insert')
+      .mockRejectedValueOnce(new Error('ClickHouse unavailable'));
+
+    await sessionBuffer.processBuffer();
+
+    // Sessions must still be in the queue — not lost
+    expect(await sessionBuffer.getBufferSize()).toBe(1);
+
+    insertSpy.mockRestore();
+  });
+});

packages/redis/cachable.test.ts

@@ -8,7 +8,10 @@ describe('cachable', () => {
   beforeEach(async () => {
     redis = getRedisCache();
     // Clear any existing cache data for clean tests
-    const keys = await redis.keys('cachable:*');
+    const keys = [
+      ...await redis.keys('cachable:*'),
+      ...await redis.keys('test-key*'),
+    ];
     if (keys.length > 0) {
       await redis.del(...keys);
     }
@@ -16,7 +19,10 @@ describe('cachable', () => {
 
   afterEach(async () => {
     // Clean up after each test
-    const keys = await redis.keys('cachable:*');
+    const keys = [
+      ...await redis.keys('cachable:*'),
+      ...await redis.keys('test-key*'),
+    ];
     if (keys.length > 0) {
       await redis.del(...keys);
     }