Alter table add clolumn hang

Hi

tape this command

ALTER TABLE user.tab1 ADD (OPTIONNAMEDEACTIVATE  VARCHAR2(128 BYTE));

select * from  v$session_wait where sid=157; returns : SQL*Net message from client

SQL> select comp_name,version,status from dba_registry;

COMP_NAME                           VERSION                        STATUS

----------------------------------- ------------------------------ -----------

Oracle Database Catalog Views       10.2.0.4.0                     VALID

Oracle Database Packages and Types  10.2.0.4.0                     VALID

JServer JAVA Virtual Machine        10.2.0.4.0                     VALID

Oracle XDK                          10.2.0.4.0                     VALID

Oracle Database Java Packages       10.2.0.4.0                     VALID

Oracle Expression Filter            10.2.0.4.0                     VALID

Oracle Enterprise Manager           10.2.0.4.0                     VALID

Oracle XML Database                 10.2.0.4.0                     VALID