Script to detect TX blocking locks

Following script detects TX blocking looks:

set linesize 160
set trimspool on
column name format A28
column type format A18
column sid format 9999
column block format 99
column ctime format 99999
column serial format 99999
column id1 format 99999999
column id2 format 99999999
column LMODE format A12
column request format A12
spool log.lock

select /*+ ordered use_merge(X$KSUSE X$KSQEQ) */
    l.ctime as ctime,
    l.sid,
    s.SERIAL# as serial,
    substr(s.USERNAME,1,8) as  username,
    substr(s.osuser,1,8) as osuser,
    substr(s.PROGRAM,1,15) as program,
    l.id1,
    l.id2,
    o.name,
    decode(l.type,
    'MR', 'MR, Media Recovery',
    'RT','RT, Redo Thread',
    'UN', 'UN, User Name',
    'TX', 'TX, Transaction',
    'TM', 'TM, DML',
    'UL', 'UL, PL/SQL User Lock',
    'DX', 'DX, Distributed Xaction',
    'CF', 'CF, Control File',
    'IS', 'IS, Instance State',
    'FS', 'FS, File Set',
    'IR', 'IR, Instance Recovery',
    'ST', 'ST, Disk Space Transaction',
    'TS', 'TS, Temp Segment',
    'IV', 'IV, Library Cache Invalidation',
    'LS', 'LS, Log Start or Switch',
    'RW', 'RW, Row Wait',
    'SQ', 'SQ, Sequence Number',
    'TE', 'TE, Extend Table',
    'TT', 'TT, Temp Table',
    l.type) as type,
    decode(lmode,0,'None',
        1,'Null',
        2,'Row-S(SS)',
        3,'Row-X(SX)',
        4,'Share',
        5,'S/Row-X(SSX)',
        6,'Exclusive',
        'Unkwon') as Lmode,
    decode(request,0,'None',
        1,'Null',
        2,'Row-S(SS)',
        3,'Row-X(SX)',
        4,'Share',
        5,'S/Row-X(SSX)',
        6,'Exclusive',
        'Unkwon') as request,
    l.block
from v$lock l, v$session s, sys.obj$ o
where l.sid = s.sid
and l.id1 = o.obj# (+)
and ( request <> 0 OR l.block =1)
order by l.sid,o.name
/