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ORA-12502 TNS-12502 TNS:listener received no CONNECT_DATA from client
- November 5, 2021
- Posted by: admin
- Category: Oracle DBA Technology Blog
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ORA-12502 TNS-12502 TNS:LISTENER RECEIVED NO CONNECT_DATA FROM CLIENT

TNS:listener received no CONNECT_DATA from client
Cause:No CONNECT_DATA was passed to the listener.
Action: Check that the service name resolved from TNSNAMES.ORA has the CONNECT_DATA component of the connect descriptor.
Below is the sample entry of tnsnames.ora:-
#When using SERVICE_NAME in CONNECT_DATA component orcl.example.com = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = myserver.example.com)(PORT = 1521)) ) (CONNECT_DATA = (SERVICE_NAME = orcl) ) ) #When using SID in CONNECT_DATA component orcl.example.com = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = myserver.example.com)(PORT = 1521)) ) (CONNECT_DATA = (SID = orcl) ) )
So for the service name please ensure you have the CONNECT_DATA clause in the tnsnames.ora, if you don’t have one please choose a SERVICE_NAME or SID clause.
ORA-12502 TNS-12502 TNS:LISTENER RECEIVED NO CONNECT_DATA FROM CLIENT

TNS:listener received no CONNECT_DATA from client
Cause:No CONNECT_DATA was passed to the listener.
Action: Check that the service name resolved from TNSNAMES.ORA has the CONNECT_DATA component of the connect descriptor.
Below is the sample entry of tnsnames.ora:-
#When using SERVICE_NAME in CONNECT_DATA component orcl.example.com = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = myserver.example.com)(PORT = 1521)) ) (CONNECT_DATA = (SERVICE_NAME = orcl) ) ) #When using SID in CONNECT_DATA component orcl.example.com = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = myserver.example.com)(PORT = 1521)) ) (CONNECT_DATA = (SID = orcl) ) )