查询当前数据库是否存在阻塞的情况

select s1.inst_id,       sl.username  blkg_user,       sl.machine   blkg_ws,       s1.sid       blkg_sid       s2.username  wait_user,       s2.machine   wait_ws,       s2.sid       wait_sid,       lo.object_id blkd_obj_id,       do.owner,       do.object_name,       l1.block,       l2.request,       l1.typefrom gv$lock l1,     gv$session s1,     gv$lock    l2,     gv$session s2,     gv$locked_object lo,     dba_objects    dowhere   l1.id1=l2.id1and l1.sid=s1.sidand l2.sid=s2.sidand s1.sid=lo.session_idand lo.object_id=do.object_idand l1.block=1and l2.request>0;

block=0，表示没有阻塞别人，=1表示当前执有的锁正阻塞别人

request:表示请求锁