Use (UR=A) with (CONNECT_DATA=(SERVICE_NAME=SERVICE))
Connection using SERVICE_NAME without (UR=A) would error with ORA-12528: TNS:listener: all appropriate instances are blocking new connections
TESTUA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = hal)(PORT = 1525))
)
(CONNECT_DATA =
(SERVICE_NAME = v10g.uk.oracle.com)
(UR = A)
)
)
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = hal)(PORT = 1525))
)
(CONNECT_DATA =
(SERVICE_NAME = v10g.uk.oracle.com)
(UR = A)
)
)
Please note that the (UR=A) clause is intended to work with a dynamically registered handler so the use of SERVICE_NAME versus SID is preferred.