Oracle DBA – A lifelong learning experience

Oracle Database 11g: Interactive Quick Reference

Posted by John Hallas on December 15, 2010

I posted a note on the Oracle-L mailing list last week covering the Oracle Database 11g: Interactive Quick Reference which has been released by Oracle.  The comments that came back were not particularly positive – ‘only for windows’, ‘not as good as the documentation’, ‘nice beta version, looking forward to the major release’. Personally I think it is pretty cool for free and the list of background processes is very good. It also sounds like it will be enhanced when 12G comes out. There is also  a SWF version of the IQR (click here for download page) so that Mac OS and Linux users don’t have to use the .EXE version.

THE IQR is a download from OTN which provides an architecture diagram of the key processes, memory structures and files. It also contains a categorization of the background processes, plus which ones are started by default, which ones are required (i.e cannot be killed without taking down the instance), and which ones are new (the background processes table in the documentation doesn’t include all of this info). Finally it shows which v$views relate to which category (redo logging, memory management etc).

However Yong Huang threw a snippet into the discussion that I thought was worth mentioning and it was certainly not something I was aware of. I have copied his post in below

Beginning with 10g, Oracle background processes on Linux/UNIX have an environment variable SKGP_HIDDEN_ARGS. On Linux, the variable is assigned a value and its first attribute can tell you whether killing this process would crash the instance:

$ ps eww $(pgrep -f ora_pmon_$ORACLE_SID) | perl -nle ‘print $& if



$ ps eww $(pgrep -f ora_mmon_$ORACLE_SID) | perl -nle ‘print $& if



If the first attribute is BG, killing the process will not crash the instance; if it’s FATAL, it will.

You don’t need to remember the complicated command. Just type `ps eww <pid>’  on Linux or `pargs -e <pid>’ on Solaris and check the environment variable.  Normally SKGP_HIDDEN_ARGS is at the end.


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