Multiple Client Versions

When schema changes are additive, old clients would just ignore the new tables and columns, and no special handling is required. However, in some cases, the schema changes may be more drastic and may need separate Sync Rules based on the client version.

To distinguish between client versions, we can pass in an additional client parameter from the client to the PowerSync Service instance. These parameters could be used to implement different logic based on the client version.

Example to use different table names based on the client’s schema_version:

# Client passes in: "params": {"schema_version": <version>}
  assets_v1:
    parameters: SELECT request.user_id() AS user_id
      WHERE request.parameters() ->> 'schema_version' = '1'
    data:
      - SELECT * FROM assets AS assets_v1 WHERE user_id = bucket.user_id

  assets_v2:
    parameters: SELECT request.user_id() AS user_id
      WHERE request.parameters() ->> 'schema_version' = '2'
    data:
      - SELECT * FROM assets AS assets_v2 WHERE user_id = bucket.user_id