ORA-01157: cannot identify/lock data file

While starting up a database, you may face following error messages which would not allow you to open the database.

ORA-01157: cannot identify/lock data file <file#> - see DBWR trace file
ORA-01110: data file <file#>: <file_name>

Manual upgrading Oracle database 11g to 12c

If you want to know how we upgrade an 11g database to 12c using DBUA, click here. 

For upgrading 12.1.0.1 to 12.1.0.2 using DBUA, click here.

This article explains how to upgrade 11.2.0.2 and above, and 12.1.0.1 to 12.1.0.2 manually.

For details of each step, take a look at official 12c

ORACLE.EXE (SHAD) Processes Keep Increasing

On Windows based Oracle installations, if you hit an issue whereby you see that processes/sessions keep increasing unabated, and you keep receiving “ORA-00020: maximum number of processes exceeded” error while connecting to the database and increasing the value of parameter “processes” remains insufficient always,

ORA-00020: maximum number of processes exceeded

You may face this error message while connecting to the database instance which will also hinder you from connecting with the database instance. The reason of this error is the value of init parameter “processes” which requires to be increased to allow Oracle instance to span a new process for new session request. For example, if value of this parameter is set to 100,

The OracleService service terminated unexpectedly

On Windows platform, the OS level service which has a name like “OracleService<SID>”, needs to be running for the database to work. If this service stops, database also stops. You may be in a situation where you receive complaints about database sudden crash, which requires DBA intervention to start this service and database.

ORA-06553: PLS-801: internal error [56319]

You will face this error while connecting to a database which has word size (32-bit or 64-bit) different than the actual installation binaries (32-bit or 64-bit). It means that if database was created (and running) on a 64-bit platform and then you move/restore same database to a 32-bit platform, or vice versa, you will be facing this problem.

OEM Database Control Setup fails with ACCESS DENIED error

On Windows platform, if OEM Database Control configuration fails with “SEVERE: Error instantiating EM configuration files” message, this could be because of permission issue of the OS user doing the OEM configuration. See bellow

C:\Users>emca -config dbcontrol db -repos create