Source Database Setup
Configure your backend database for PowerSync, including permissions and replication settings.
Jump to: Postgres | MongoDB | MySQL
Postgres
Version compatibility: PowerSync requires Postgres version 11 or greater.
Configuring your Postgres database for PowerSync generally involves three tasks:
- Enable logical replication
- Create a PowerSync database user
- Create
powersync
logical replication publication
We have documented steps for some hosting providers:
Supabase
Supabase
1. Enable logical replication
Supabase has logical replication enabled by default — no action required.
2. Create a PowerSync database user
To restrict read access to specific tables, explicitly list allowed tables for both the SELECT
privilege, and for the publication mentioned in the next step (as well as for any other publications that may exist).
3. Create “powersync” publication
AWS RDS
AWS RDS
Prerequisites
The instance must be publicly accessible using an IPv4 address.
Access may be restricted to specific IPs if required — see IP Filtering.
1. Enable logical replication
Set the rds.logical_replication
parameter to 1
in the parameter group for the instance:
2. Create a PowerSync database user
Create a PowerSync user on Postgres:
To restrict read access to specific tables, explicitly list allowed tables for both the SELECT
privilege, and for the publication (as well as for any other publications that may exist).
3. Create “powersync” publication
Azure Postgres
Azure Postgres
PowerSync supports both “Azure Database for PostgreSQL” and “Azure Database for PostgreSQL Flexible Server”.
Prerequisites
The database must be accessible on the public internet. Once you have created your database, navigate to Settings → Networking and enable Public access.
1. Enable logical replication
Follow the steps as noted in this Microsoft article to allow logical replication.
2. Create a PowerSync database user
To restrict read access to specific tables, explicitly list allowed tables for both the SELECT
privilege, and for the publication mentioned in the next step (as well as for any other publications that may exist).
3. Create “powersync” publication
Google Cloud SQL
Google Cloud SQL
1. Enable logical replication
In Google Cloud SQL Postgres, enabling the logical replication is done using flags:
2. Create a PowerSync database user
To restrict read access to specific tables, explicitly list allowed tables for both the SELECT
privilege, and for the publication mentioned in the next step (as well as for any other publications that may exist).
3. Create “powersync” publication
Neon
Neon
Neon is a serverless Postgres environment with an innovative pricing model that separates storage and compute.
1. Enable Logical Replication
To enable logical replication:
- Select your project in the Neon Console.
- On the Neon Dashboard, select Settings.
- Select Logical Replication.
- Click Enable to enable logical replication.
2. Create a PowerSync database user
To restrict read access to specific tables, explicitly list allowed tables for both the SELECT
privilege, and for the publication mentioned in the next step (as well as for any other publications that may exist).
3. Create “powersync” publication
Fly Postgres
Fly Postgres
Fly Postgres is a Fly app with flyctl sugar on top to help you bootstrap and manage a database cluster for your apps.
1. Enable logical replication
Once you’ve deployed your Fly Postgres cluster, you can use the following command to enable logical replication:
2. Create a PowerSync database user
To restrict read access to specific tables, explicitly list allowed tables for both the SELECT
privilege, and for the publication mentioned in the next step (as well as for any other publications that may exist).
3. Create “powersync” publication
PlanetScale
PlanetScale
1. Enable logical replication
wal_level = logical
is required and PlanetScale has this set by default - no action needed.
2. Create a PowerSync database user
To restrict read access to specific tables, explicitly list allowed tables for both the SELECT
privilege, and for the publication mentioned in the next step (as well as for any other publications that may exist).
3. Create “powersync” publication
For other providers and self-hosted databases:
Other / Self-hosted
Other / Self-hosted
Need help? Simply contact us on Discord and we’ll help you get set up.
1. Enable logical replication
PowerSync reads the Postgres WAL using logical replication in order to create sync buckets in accordance with the specified PowerSync Sync Rules.
If you are managing Postgres yourself, set wal_level = logical
in your config file:
Alternatively, you can use the below SQL commands to check and enable logical replication:
Note that Postgres must be restarted after changing this config.
If you’re using a managed Postgres service, there may be a setting for this in the relevant section of the service’s admin console.
2. Create a PowerSync database user
To restrict read access to specific tables, explicitly list allowed tables for both the SELECT
privilege, and for the publication mentioned in the next step (as well as for any other publications that may exist).
3. Create “powersync” publication
Unsupported Hosted Postgres Providers
Due to the logical replication requirement, not all Postgres hosting providers are supported. Notably, some “serverless Postgres” providers do not support logical replication, and are therefore not supported by PowerSync yet.
MongoDB
Version compatibility: PowerSync requires MongoDB version 6.0 or greater.
Permissions required - MongoDB Atlas
For MongoDB Atlas databases, the minimum permissions when using built-in roles are:
To allow PowerSync to automatically enable changeStreamPreAndPostImages
on replicated collections (the default for new PowerSync instances), additionally add the dbAdmin
permission:
If you are replicating from multiple databases in the cluster, you need read permissions on the entire cluster, in addition to the above:
Privileges required - Self-hosted / Custom roles
For self-hosted MongoDB, or for creating custom roles on MongoDB Atlas, PowerSync requires the following privileges/granted actions:
- On the database being replicated:
listCollections
- On all collections in the database:
changeStream
- This must apply to the entire database, not individual collections. Specify
collection: ""
- If replicating from multiple databases, this must apply to the entire cluster. Specify
db: ""
- This must apply to the entire database, not individual collections. Specify
- On each collection being replicated:
find
- On the
_powersync_checkpoints
collection:createCollection
,dropCollection
,find
,changeStream
,insert
,update
, andremove
- To allow PowerSync to automatically enable
changeStreamPreAndPostImages
on replicated collections, additionally add thecollMod
permission on all replicated collections.
Post-Images
To replicate data from MongoDB to PowerSync in a consistent manner, PowerSync uses Change Streams with post-images to get the complete document after each change.
This requires the changeStreamPreAndPostImages
option to be enabled on replicated collections.
PowerSync supports three configuration options for post-images:
- Off: (
post_images: off
): UsesfullDocument: 'updateLookup'
for backwards compatibility. This was the default for older instances. However, this may lead to consistency issues, so we strongly recommend enabling post-images instead. - Automatic: (
post_images: auto_configure
) The default for new instances: Automatically enables thechangeStreamPreAndPostImages
option on collections as needed. Requires the permissions/privileges mentioned above. If a collection is removed from Sync Rules, developers can manually disablechangeStreamPreAndPostImages
. - Read-only: (
post_images: read_only
): UsesfullDocument: 'required'
and requireschangeStreamPreAndPostImages: { enabled: true }
to be set on every collection referenced in the Sync Rules. Replication will error if this is not configured. This option is ideal when permissions are restricted.
To manually configure collections for read_only
mode, run this on each collection:
You can view which collections have the option enabled using:
Post-images can be configured for PowerSync instances as follows:
PowerSync Cloud:
Configure the Post Images setting in the connection configuration in the Dashboard (right-click on your instance to edit it).
Self-Hosted PowerSync:
Configure post_images
in the config.yaml
file.
MongoDB Atlas private endpoints using AWS PrivateLink
If you need to use private endpoints with MongoDB Atlas, see Private Endpoints (AWS only).
Migrating from MongoDB Atlas Device Sync
For more information on migrating from Atlas Device Sync to PowerSync, see our migration guide.
MySQL (Alpha)
This section is a work in progress. More details for MySQL connections are coming soon. In the meantime, ask on our Discord server if you have any questions.
Version compatibility: PowerSync requires MySQL version 5.7 or greater.
MySQL connections use the binary log to replicate changes.
Generally, this requires the following config:
gtid_mode
:ON
enforce_gtid_consistency
:ON
binlog_format
:ROW
PowerSync also requires a user with replication permissions on the database. An example:
Next Step
Next, connect PowerSync to your database: