Global Application Contexts in an Oracle Real Application Clusters Environment

In an Oracle RAC environment, whenever a global application context is loaded or changed, it is visible only to the existing active instances.

Be aware that setting a global application context value in an Oracle RAC environment has performance overhead of propagating the context value consistently to all Oracle RAC instances.

If you flush the global application context (using the ALTER SYSTEM FLUSH GLOBAL_CONTEXT SQL statement) in one Oracle RAC instance, then all the global application context is flushed in all other Oracle RAC instances as well.