Latch, mutex and beyond


     This file is part of demos for "Mutex Internals"   seminar v.04.04.2011
     Andrey S. Nikolaev ( 

     Sessions currently waiting for mutexes
     Some columns were not printed to fit linesize 80. You can adjust this.

     usage: @mutex_waits
col sid format 9999
col serial# noprint format 9999
col event format a19
col blocking_sid heading "BLKS" format 9999
col shared_refcount heading "RFC" format 99
col location_id heading "LOC" format 99
col sleeps  noprint format 99999
col mutex_object format a15
set wrap off

SELECT SID,serial#,sql_id,event,p1 idn,
            FLOOR (p2/POWER(2,4*ws)) blocking_sid,MOD (p2,POWER(2,4*ws)) shared_refcount,
            FLOOR (p3/POWER (2,4*ws)) location_id,MOD (p3,POWER(2,4*ws)) sleeps,
            CASE WHEN (event LIKE 'library cache:%' AND p1 <= power(2,17)) THEN  'library cache bucket: '||p1 
                    ELSE  (SELECT kglnaobj FROM x$kglob WHERE kglnahsh=p1 AND (kglhdadr = kglhdpar) and rownum=1) END mutex_object
       FROM (SELECT DECODE (INSTR (banner, '64'), 0, '4', '8') ws FROM v$version WHERE ROWNUM = 1) wordsize, 
       WHERE p1text='idn' AND state='WAITING';


  1. […] mutex_waits.sql – list sessions currently waiting for mutexes […]

    Pingback by “Cursor: pin S” mutex contention testcase and diagnostics tools. « Latch, mutex and beyond — April 22, 2011 @ 4:33 pm | Reply

  2. Thank you

    Comment by siddiqy — May 30, 2011 @ 8:32 pm | Reply

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