Locking the SGA

Pretty much every tuning manual specifies that some order of benefit can be found by locking the SGA into memory. However, typically the manuals specify that simply issuing 'lock_sga = true' in init.ora will take care of that.

This may be the case on your platform, but on many unixes, the oracle account must be granted unix level privileges to be allowed to do this.

To give the oracle Unix user memory locking privileges at the OS level:

  1. Login as root
  2. Create the file "/etc/privgroup"
  3. Add line "dba MLOCK" to file (assuming 'dba' is the appropriate unix group)
  4. As root, run the command "/etc/setprivgrp -f /etc/privgroup":