dbca deleteDatabase removes listener alias from tnsnames.ora

I have two databases ORCL, MYDB. Each of them has LOCAL_LISTENER  set to listener alias NODEFQDN that is described in tnsnames.ora.

[oracle@rac1 ~]$ cat /u01/app/oracle/product/12.2.0/dbhome_1/network/admin/tnsnames.ora

NODEFQDN =
(ADDRESS = (PROTOCOL = TCP)(Host = rac1.mydomain.com)(Port = 1522))

ORCL =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = maritest-scan.mydomain.com)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = orcl)))

MYDB =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = maritest-scan.mydomain.com)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = mydb)))

[oracle@rac1 ~]$ sqlplus mari@ORCL
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 – 64bit Production

SQL> show parameter local_listener

NAME TYPE VALUE
———————————— ———– ——————————
local_listener string NODEFQDN

[oracle@rac1 ~]$ sqlplus mari@MYDB
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 – 64bit Production

SQL> show parameter local_listener

NAME TYPE VALUE
———————————— ———– ——————————
local_listener string NODEFQDN

I have deleted ORCL database using dbca :

[oracle@rac1 ~]$ dbca -silent -deleteDatabase -sourceDB orcl
Enter SYS user password:

Connecting to database 9% complete 14% complete 19% complete 23% complete 28% complete 33% complete 38% complete 47% complete
Updating network configuration files 48% complete 52% complete
Deleting instances and datafiles 66% complete 80% complete 95% complete 100% complete
Look at the log file “/u01/app/oracle/cfgtoollogs/dbca/orcl.log” for further details.

Checked tnsnames.ora and see that NODEFQDN alias is deleted:

[oracle@rac1 ~]$ cat /u01/app/oracle/product/12.2.0/dbhome_1/network/admin/tnsnames.ora

MYDB =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = maritest-scan.mydomain.com)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = mydb)))

Problem is that MYDB still has LOCAL_LISTENER=NODEFQDN. It means when I restart MYDB database it will not automatically be registered with the listener because tns does not contain NODEFQDN anymore.

Identified that, deletion of this entry depends on LOCAL_LISTENER parameter. If it is set to this alias then during db deletion that entry  is also deleted(unfortunatelly, dbca does not consider if that entry is used by other dbs) . If the parameter is empty or has the value :  (ADDRESS = (PROTOCOL = TCP)(Host = rac1.mydomain.com)(Port = 1522)) then entry stays in tnsnames.ora after db deletion.

To prevent dbca delete that entry from tnsnames.ora even LOCAL_LISTENER is set to NODEFQDN. There exist one trick:

In tnsnames.ora single entry can have multiple aliases, this is not docummented but seems we have a lot of hidden features:

Example:

alias1,alias2, alias3 =
(DESCRIPTION=
(ADDRESS=(PROTOCOL=tcp)(HOST=hostname)(PORT=1521))
(CONNECT_DATA=
(SERVICE_NAME=service_name)))

You can have blank spaces between aliases or not have, just you must separate them by commas.

So in our case we can write like this:

DONOTDELETE,NODEFQDN =
(ADDRESS = (PROTOCOL = TCP)(Host = rac1.mydomain.com)(Port = 1522))

It is up to you what will be the first alias 🙂 You may write DBCADOTTOUCH ))

Each alias is resolvable:

[oracle@rac1 ~]$ tnsping NODEFQDN
..
Used TNSNAMES adapter to resolve the alias
Attempting to contact (ADDRESS = (PROTOCOL = TCP)(Host = rac1.mydomain.com)(Port = 1522))
OK (0 msec)

[oracle@rac1 ~]$ tnsping DONOTDELETE
..
Used TNSNAMES adapter to resolve the alias
Attempting to contact (ADDRESS = (PROTOCOL = TCP)(Host = rac1.mydomain.com)(Port = 1522))
OK (0 msec)

After database deletion this entry stays in tnsnames.ora

Good Luck!

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