|Range of values||0 to the maximum number of enabled threads|
|Real Application Clusters||If specified, multiple instances must have different values.|
When you create a database, Oracle creates and enables thread 1 as a public thread (one that can be used by any instance). You must create and enable subsequent threads using the
ADD LOGFILE THREAD clause and
ENABLE THREAD clause of the
ALTER DATABASE statement. The number of threads you create is limited by the
MAXINSTANCES parameter specified in the
CREATE DATABASE statement.
In exclusive mode, thread 1 is the default thread. However, you can specify
THREAD for an instance running in exclusive mode if you want to use the redo log files in a thread other than thread 1.
In parallel mode, you can specify any available redo thread number, as long as that thread number is enabled and is not in use by another instance.
A value of zero specifies that this instance can use any available, enabled public thread.