Create a database user and provide the user with READ access to all the resources which need to be migrated. Run the following commands in a psql session:

1. Create a new user named ybvoyager.

   CREATE USER ybvoyager PASSWORD 'password';
   

2. Switch to the database that you want to migrate.

   \c <database_name>
   

3. Grant the USAGE permission to the ybvoyager user on all schemas of the database.

   SELECT 'GRANT USAGE ON SCHEMA ' || schema_name || ' TO ybvoyager;' FROM information_schema.schemata; \gexec
   

   The above SELECT statement generates a list of GRANT USAGE statements which are then executed by psql because of the \gexec switch. The \gexec switch works for PostgreSQL v9.6 and later. For older versions, you'll have to manually execute the GRANT USAGE ON SCHEMA schema_name TO ybvoyager statement, for each schema in the source PostgreSQL database.

4. Grant SELECT permission on all the tables and sequences.

   SELECT 'GRANT SELECT ON ALL TABLES IN SCHEMA ' || schema_name || ' TO ybvoyager;' FROM information_schema.schemata; \gexec
   
   SELECT 'GRANT SELECT ON ALL SEQUENCES IN SCHEMA ' || schema_name || ' TO ybvoyager;' FROM information_schema.schemata; \gexec
   

   The ybvoyager user can now be used for migration.