---
title: Create a read-only replica | Tiger Data Docs
description: Create and use a read-only replica for your services in Managed Service for TimescaleDB
---

PostgreSQL read-only replicas allow you to perform read-only queries against the replica and reduce the load on the primary server. You can optimize query response times across different geographical locations because the replica can be created in different regions or on different cloud providers. For information about creating a read-only replica using the Aiven client, see the documentation on [creating a read replica using the CLI](/docs/deploy/mst/aiven-client/index.md).

Note

If you are running a Managed Service for TimescaleDB [Pro plan](/docs/deploy/mst/about-mst/index.md), you have standby nodes available in a high availability setup. The standby nodes support read-only queries to reduce the effect of slow queries on the primary node.

## Creating a replica

1. **Select the service**

   In [Managed Service for TimescaleDB Console](https://portal.managed.timescale.com/login), click the service you want to create a remote replica for.

2. **Create a read replica**

   In `Overview`, click `Create a read replica`.

3. **Configure and create**

   In `Create a PostgreSQL read replica`, type a name for the remote replica, select the cloud provider, location, plan that you want to use, and click `Create`.

When the read-only replica is created it is listed as a service in your project. The `Overview` tab of the replica also lists the name of the primary service for the replica. To promote a read-only replica as a master database, click the `Promote to master` button.

## Using read-only replica for the service on MST

1. **Copy the Service URI**

   In the `Overview` page of the read-only replica for the service on MST, copy the `Service URI`.

2. **Connect to the read-only service**

   At the psql prompt, connect to the read-only service:

   ```
   psql <SERVICE_URI>
   ```

3. **Check the connection type**

   To check whether you are connected to a primary or replica node:

   ```
   SELECT * FROM pg_is_in_recovery();
   ```

   If the output is `TRUE` you are connected to the replica, and if the output is `FALSE` you are connected to the primary server.

Note

Managed Service for TimescaleDB uses asynchronous replication, so some lag is expected. When you run an `INSERT` operation on the primary node, a small delay of less than a second is expected for the change to propagate to the replica.