> ## Documentation Index
> Fetch the complete documentation index at: https://upstash-vector.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# ERR max concurrent connections exceeded

### Symptom

New clients can not connect to the database throwing an exception similar to:

```
"message" : "[ioredis] Unhandled error event:
ReplyError: ERR max concurrent connections exceeded\r
at Object.onceWrapper (events.js:286:20)\r
at Socket.emit (events.js:203:15)\r    at Socket.EventEmitter.emit (domain.js:448:20)\r
at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1093:10)\n"
```

### Diagnosis

You have reached the concurrent connection limit.

### Solution-1

You need to manage connections more efficiently. If you are using serverless
functions, you can create the Redis client inside the function and close the
connection when you are done with the database as below.

<Note>
  This solution may have a latency overhead (about 4 ms). See [the blog
  post](https://blog.upstash.com/serverless-database-connections) for more.
</Note>

```javascript
exports.handler = async (event) => {
  const client = new Redis(process.env.REDIS_URL);
  /*
    do stuff with redis
     */
  await client.quit();
  /*
  do other stuff
   */
  return {
    response: "response",
  };
};
```

### Solution-2

You can use [@upstash/redis](https://github.com/upstash/upstash-redis) client
which is REST based so it does not have any connection related problems.

### Solution-3

You can upgrade your database to Pro/Enterprise for higher limits.

<Info>
  See [the blog post](https://blog.upstash.com/serverless-database-connections)
  about the database connections in serverless functions.
</Info>