ORA-27123 error during oracle database start

Issue
While starting the oracle database 10g [10.1.0.5.0], we get the following error.

ORA-27123: unable to attach to shared memory segment

How to delete tempfile in temporary tablespace in Oracle database

First identify the temporary tablespace and corresponding datafiles issuing following command.

How to Disable all scheduled Concurrent Request in R12

The following query will disable all the scheduled concurrent request in Oracle R12.

How to use Logminer to analyze the archive log

Here is a simple example of using logminer to analyze redo or archive logs.

opidcl aborting process unknown ospid (xxxx_xxxxxxx) due to error ORA-28

In oracle database version 11.1.0.7, we have encountered the following error message.
opidcl aborting process unknown ospid (12874_47230856307152) due to error ORA-28