Postgres: Streaming subscriptions
A streaming subscription streams the response according to the cursor provided by the user while making the subscription. Streaming subscriptions can be used to subscribe only to the data which has been newly added to the result set.
Streaming subscriptions are supported in Hasura GraphQL engine versions
v2.7.0-beta.1 and above.
Streaming subscriptions in the graphql-engine are disabled by default. To enable it, set the environment variable
How it works?
In streaming subscriptions, the server maintains a cursor value with a subscription and after streaming each batch, the value of the cursor is updated. Ideally, the cursor chosen should represent unique and sortable values so that each row is sent exactly once to a subscriber.
In the case of streaming subscriptions, the multiplexed batch size can be configured via
HASURA_GRAPHQL_STREAMING_QUERIES_MULTIPLEXED_BATCH_SIZE and the refetch interval can be configured via