Read replicas¶

Introduction¶

Hasura Cloud can load balance queries and subscriptions across read replicas while sending all mutations and metadata API calls to the master.

Adding read replica urls¶

If you have configured your Postgres instances with replicas, the replica URLs can be added to Hasura using the following environment variable in your project ENV Vars tab:

HASURA_GRAPHQL_READ_REPLICA_URLS=postgres://user:password@replica-host:5432/db

If you have multiple replicas, their urls can be added as comma separated values.

Connection pool parameters¶

Additional environment variables for connection pools, and for read replicas specifically:

HASURA_GRAPHQL_PG_STRIPES

HASURA_GRAPHQL_PG_CONNECTIONS

HASURA_GRAPHQL_CONNECTIONS_PER_READ_REPLICA

HASURA_GRAPHQL_STRIPES_PER_READ_REPLICA