Queries made using reference jobs on the standby server may be canceled by jobs executed on the primary server.
To reduce the possibility of a job being canceled, specify as large a value as possible for the max_standby_archive_delay parameter in the postgresql.conf file.
See
Refer to "Handling Query Conflicts" in the PostgreSQL Documentation for details.
Refer to "Standby Servers" in the PostgreSQL Documentation for details on the max_standby_archive_delay parameter.