ORA-12546: TNS:permission denied

I recently faced this error message while trying to connect with the database (running on my local Windows host) using a TNS service. Although connecting without TNS service was working fine, however, connection was failing with ORA-12546 when I tried to connect using TNS service. Following is what I faced.

ORA-01511 and ORA-01523

While renaming a datafile or redo log file you might face these both errors together and command would fail as shown below.

SQL> ALTER DATABASE RENAME FILE ‘d:\oracle\oradata\db\users01.dbf’ to ‘e:\oracle\oradata\users01.dbf’; ALTER DATABASE RENAME FILE ‘d:\oracle\oradata\db\users01.dbf’ to ‘e:\oracle\oradata\users01.dbf’; * ERROR at line 1: ORA-01511: error in renaming log/data files ORA-01523: cannot rename datafile to d:\oracle\oradata\db\users01.dbf’ – File already part of database

ORA-01000: maximum open cursors exceeded

Cursor is a pointer to a memory area which is opened to execute an SQL statement issued by the end user/application. It means that every SQL (SELECT/DML) you want to execute would require utilizing this memory area to execute the SQL.

ORA-01186 ORA-01157 ORA-01111 ORA-01110

Managed Standby Recovery starting Real Time Apply
Thu Sep 19 04:05:35 2019
Errors in file /u01/app/oracle/diag/rdbms/mydb/mydb/trace/rgb1p117_dbw0_10657.trc:
ORA-01186: file 166 failed verification tests
ORA-01157: cannot identify/lock data file 166 - see DBWR trace file
ORA-01111: name for data file 166 is unknown - rename to correct file
ORA-01110: data file 166: '/u01/app/oracle/product/12.1.0/dbhome_1/dbs/UNNAMED00166'
Thu Sep 19 04:05:35 2019
File 166 not verified due to error ORA-01157
Thu Sep 19 04:05:35 2019

ORA-01438: value larger than specified precision allowed for this column

You may also want to see this article about the ORA-12899 which is returned if a value larger than column’s width is inserted in the column. Similarly, ORA-01438 is returned if value being inserted is larger than what is defined for the NUMBER datatype column. Number datatype columns are defined in precision and scale (NUMBER(p,s)). If you define a number column as “NUMBER(5,2)”, it would mean that maximum width of the data could be 5 digits, out of which 2 will be decimal part (for example 123.45). Following are some examples that explain this concept further.

ORA-12899: value too large for column...

You may want to learn about a similar error message ORA-01438 caused by larger values being inserted in NUMBER columns. 
Message displayed with error ORA-12899 is self-explained. This error would come if you are trying to insert into a table’s column which is not big enough to hold the data being inserted. Suppose you define a column with a width of 10 characters (VARCHAR2(10)), and later if you try to insert a value longer than 10 characters, ORA-12899 would be returned. To solve this problem you can either reduce the data width being inserted, or alternatively increase the column width. If you have a multi-byte database characterset,  a VARCHAR2 column with a width of 10 may not store exactly 10 characters. Following is one example to produce ORA-12899.

DBUA Does not Find parameter file to Start Database for Upgrade

While upgrading my database form using database upgrade assistant (DBUA), it showed me error that said following

The Upgrade Assistant failed in bringing up the database <db_name>. Oracle Home <ORACLE_HOME> obtained from file /etc/oratab was used to connect to the database. Either database is not running from Oracle Home <ORACLE_HOME> or correct initialization Parameter file (pfile) was not found. To start the database, Oracle needs the pfile. Provide the full path name of the init file for the database <db_name>

Screenshot of DBUA can be seen bellow

PING[ARC1]: Heartbeat failed to connect to standby 'my_standby'. Error is 12154

If your primary database is not able to ship archived logs to the standby database with error ORA-12154, there is something wrong with the TNS entry you are using in LOG_ARCHIVE_DEST_n parameter that points to your standby database. If you check the alert log file of the primary database you will see error messages similar to the following.

kkjcre1p: unable to spawn jobq slave process, slot 2, error 1089

If you have initiated SHUTDOWN command to stop the database, new sessions cannot connect with the database. This means that even oracle scheduled jobs also cannot be initiated internally. After initiation of SHUTDOWN, if any scheduled jobs get initiated (because scheduled time of any job has reached), job would not be started and an error message will be logged in the alert log file. Following is how alert log would look like after that. Since this is just an information message, therefore  no action is needed.

ORA-39700: database must be opened with UPGRADE option

This message would appear if you have opened a database from a newer version ORACLE_HOME instead of the current version of the database. Alert logs shows messages similar to the following when you open your database with “startup open” command. Instance would immediately crash after logging these messages in the alert log file.