dba_lock
Name Type
----------------- -------------
SESSION_ID NUMBER
LOCK_TYPE VARCHAR2(26)
MODE_HELD VARCHAR2(40)
MODE_REQUESTED VARCHAR2(40)
LOCK_ID1 VARCHAR2(40)
LOCK_ID2 VARCHAR2(40)
LAST_CONVERT NUMBER
BLOCKING_OTHERS VARCHAR2(40)
DBA_LOCK lists all locks or latches held in the database, and all outstanding requests for a lock. To see this in action lets create a simple table put a couple of rows in it and then create a lock. Begin by creating a table and inserting a row into it (don't commit):
create table test_table (
id number primary key
, text varchar2(100)
)
/
insert into test_table values(1, 'hello');
If you then run the following query, you will see that you have a lock on the uncommitted row:
select lock_type
, mode_held
, blocking_others
from dba_locks l
, dba_objects o
where l.lock_id1 = o.object_id
and o.object_name = 'TEST_TABLE'
/
LOCK_TYPE MODE_HELD BLOCKING_OTHERS
------------ ---------- --------------------
DML Row-X (SX) Not Blocking
As soon as you commit, the lock will disappear.
For more useful DBA queries click here.
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