- 10 Nov, 2021
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ORA-00054: resource busy and acquire with NOWAIT specified
ORA-00054: resource busy and acquire with NOWAIT specified
ORA-00054: resource busy and acquire with NOWAIT specified
Cause: The NOWAIT keyword forced a return to the command prompt because a resource was unavailable for a LOCK TABLE or SELECT FOR UPDATE command.
Action: Try the command after a few minutes or enter the command without the NOWAIT keyword.
Example:
SQL> alter table emp add (mobile varchar2(15)); * ERROR at line 1: ORA-00054: resource busy and acquire with NOWAIT specified
How to avoid the ORA-00054:
- Execute DDL at off-peak hours, when database is idle.
- Execute DDL in maintenance window.
- Find and Kill the session that is preventing the exclusive lock.
Other Solutions:
Solution 1:
In Oracle 11g you can set ddl_lock_timeout i.e. allow DDL to wait for the object to become available, simply specify how long you would like it to wait:
SQL> alter session set ddl_lock_timeout = 600; Session altered.
SQL> alter table emp add (mobile varchar2(15)); Table altered.
Solution 2:
Also In 11g, you can mark your table as read-only to prevent DML:
<pre>SQL> alter table emp read only; Session altered.</pre>
SQL> alter table emp add (mobile varchar2(15)); Table altered.
Solution 3 (for 10g):
DECLARE
MYSQL VARCHAR2(250) := 'alter table emp add (mobile varchar2(15))';
IN_USE_EXCEPTION EXCEPTION;
PRAGMA EXCEPTION_INIT(IN_USE_EXCEPTION, -54);
BEGIN
WHILE TRUE LOOP
BEGIN
EXECUTE IMMEDIATE MYSQL;
EXIT;
EXCEPTION
WHEN IN_USE_EXCEPTION THEN
NULL;
END;
DBMS_LOCK.SLEEP(1);
END LOOP;
END;
Solution 4:
Step 1: Identify the session which is locking the object
select a.sid, a.serial# from v$session a, v$locked_object b, dba_objects c where b.object_id = c.object_id and a.sid = b.session_id and OBJECT_NAME='EMP';
Step 2: kill that session using
alter system kill session 'sid,serial#';