Database

Replication

Replication is a technique for copying the data from one database to another. Supabase uses replication functionality to provide a real-time API. Replication is useful for:

  • Spreading out the "load." For example, if your database has a lot of reads, you might want to split it between two databases.
  • Reducing latency. For example, you may want one database in London to serve your European customers, and one in New York to serve the US.

Replication is done through publications, a method of choosing which changes to send to other systems (usually another Postgres database). Publications can be managed in the Dashboard or with SQL.

Manage publications in the dashboard

  1. Go to the Database page in the Dashboard.
  2. Click on Publications in the sidebar.
  3. Control which database events are sent by toggling Insert, Update, and Delete.
  4. Control which tables broadcast changes by selecting Source and toggling each table.

Create a publication

This publication contains changes to all tables.

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create publication publication_namefor all tables;

Create a publication to listen to individual tables

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create publication publication_namefor table table_one, table_two;

Add tables to an existing publication

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alter publication publication_nameadd table table_name;

Listen to insert

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create publication publication_namefor all tableswith (publish = 'insert');

Listen to update

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create publication publication_namefor all tableswith (publish = 'update');

Listen to delete

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create publication publication_namefor all tableswith (publish = 'delete');

Remove a publication

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drop publication if exists publication_name;

Recreate a publication

If you're recreating a publication, it's best to do it in a transaction to ensure the operation succeeds.

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begin;  -- remove the realtime publication  drop publication if exists publication_name;  -- re-create the publication but don't enable it for any tables  create publication publication_name;commit;