说明：

temp表空间的TS# 为 3*, So TS#+ 1= 4

一下是摘自Metalink的说明

The DROP_SEGMENTS event

~~~~~~~~~~~~~~~~~~~~~~~

Available from 8.0 onwards.

DESCRIPTION

Finds all the temporary segments in a tablespace which are not

currently locked and drops them.

For the purpose of this event a "temp" segment is defined as a

segment (seg$ entry) with TYPE#=3. Sort space in a TEMPORARY

tablespace does not qualify under this definition as such

space is managed independently of SEG$ entries.

PARAMETERS

level - tablespace number+1. If the value is 2147483647 then

temp segments in ALL tablespaces are dropped, otherwise, only

segments in a tablespace whose number is equal to the LEVEL

specification are dropped.

NOTES

This routine does what SMON does in the background, i.e. drops

temporary segments. It is provided as a manual intervention tool which

the user may invoke if SMON misses the post and does not get to

clean the temp segments for another 2 hours. We do not know whether

missed post is a real possibility or more theoretical situation, so

we provide this event as an insurance against SMON misbehaviour.

Under normal operation there is no need to use this event.

It may be a good idea to

alter tablespace coalesce;

after dropping lots of extents to tidy things up.

*SQL Session (if you can connect to the database):

alter session set events 'immediate trace name DROP_SEGMENTS level TS#+1';

The TS# can be obtained from v$tablespace view:

select ts# from v$tablespace where name = '';

Or from SYS.TS$:

select ts# from sys.ts$ where name = '' and online$ != 3;

If ts# is 5, an example of dropping the temporary segments in that tablespace

would be:

alter session set events 'immediate trace name DROP_SEGMENTS level 6';