We discovered that our Oracle 12c database was taking up a large amount of disk space with archive logs, so I figured out how to delete the files, but I’m unable to disable archive logging. We don’t have an in-house DBA, so I’m trying to figure this out myself. From lots of Googling, it’s my understanding that I need to do the following:

sqlplus / as sysdba shutdown immediate startup mount alter database noarchivelog; alter database open; 

I’ve got two problems though. I can’t do the “sqlplus / as sysdba”, it complains about “ORA-12560: TNS:protocol adapter error” unless I specify the SID, even though it the environment variable is defined. Also, when I do the shutdown, I get “ORA-12514: TNS:listener does not currently know of service requested in connect descriptor” and it disconnects me from Oracle.

C:\Users\administrator.MYDOMAIN>set oracle_sid=orcm  C:\Users\administrator.MYDOMAIN>sqlplus /nolog  SQL*Plus: Release 12.1.0.2.0 Production on Mon Feb 5 11:11:33 2018  Copyright (c) 1982, 2014, Oracle.  All rights reserved.  SQL> connect / as sysdba ERROR: ORA-12560: TNS:protocol adapter error   SQL> connect sys/password@orcm as sysdba Connected. SQL> SQL> SQL> archive log list; Database log mode              Archive Mode Automatic archival             Enabled Archive destination            E:\app\oracle\product.1.0\dbhome_1\RDBMS Oldest online log sequence     6869 Next log sequence to archive   6871 Current log sequence           6871 SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. ERROR: ORA-12514: TNS:listener does not currently know of service requested in connect descriptor   Warning: You are no longer connected to ORACLE. SQL> 

Any assistance would be greatly appreciated.