set lines 100 pages 200 /* define event="gc current block busy" define obj_cnt=10 */ col object_name format A32 col object_type format A20 col owner format A20 col cnt format 999999999 with ash_gc as (select * from ( select /*+ materialize */ inst_id, event, current_obj#, count(*) cnt from gv$active_session_history where event=lower('&event') group by inst_id,event, current_obj# having count(*) > &obj_cnt )) select * from ( select inst_id,owner, object_name,object_type, cnt from ash_gc a, dba_objects o where (a.current_obj#=o.data_object_id or a.current_obj#=o.object_id) and a.current_obj#>=1 union select inst_id, '','','Undo Header/Undo block' , cnt from ash_gc a where a.current_obj#=0 union select inst_id, '','','Undo Block' , cnt from ash_gc a where a.current_obj#=-1 ) order by 5 /