doc

    Name:    pcmbydfl.sql

    Author:  Mark Gurry

    The following query shows the number of PCM locks being used by 
    the datafile.

#

SELECT df.tablespace_name, df.file_name, buf.lock_element_addr, COUNT(*)
  FROM dba_data_files df, v$bh buf
  WHERE df.file_id = buf.file#
GROUP BY df.tablespace_name, df.file_name, buf.lock_element_addr
HAVING COUNT(*) > 1;
