Graph from v$active_session_history

Latest posts by Cyrille Modiano (see all)

Description

This query generate the data needed to build the load graph from v$active session_history, the output represent what sessions did in your database for the last hour, be careful, the v$active_session_history is part of the diagnostic pack, if you don’t have a license for this pack you should not run this query.

Query to get graph from v$active_session_history

SELECT sysmetric_history.sample_time,
  cpu/60 AS cpu,
  bcpu/60 AS bcpu,
  DECODE(SIGN((cpu+bcpu)/60-cpu_ora_consumed), -1, 0, ((cpu+bcpu)/60-cpu_ora_consumed)) AS cpu_ora_wait,
  scheduler/60 AS scheduler,
  uio/60 AS uio,
  sio/60 AS sio,
  concurrency/60 AS concurrency,
  application/60 AS application,
  COMMIT/60 AS COMMIT,
  configuration/60 AS configuration,
  administrative/60 AS administrative,
  network/60 AS network,
  queueing/60 AS queueing,
  clust/60 AS clust,
  other/60 AS other
FROM
  (SELECT
     TRUNC(sample_time,'MI') AS sample_time,
     DECODE(session_state,'ON CPU',DECODE(session_type,'BACKGROUND','BCPU','ON CPU'), wait_class) AS wait_class
   FROM v$active_session_history
   WHERE sample_time>sysdate-INTERVAL '1' HOUR
   AND sample_time<=TRUNC(SYSDATE,'MI')) ash
   PIVOT (COUNT(*) FOR wait_class IN ('ON CPU' AS cpu,'BCPU' AS bcpu,'Scheduler' AS scheduler,'User I/O' AS uio,'System I/O' AS sio,
   'Concurrency' AS concurrency,'Application' AS application,'Commit' AS COMMIT,'Configuration' AS configuration,
   'Administrative' AS administrative,'Network' AS network,'Queueing' AS queueing,'Cluster' AS clust,'Other' AS other)) ash,
   (SELECT
      TRUNC(begin_time,'MI') AS sample_time,
      VALUE/100 AS cpu_ora_consumed
    FROM v$sysmetric_history
    WHERE GROUP_ID=2
    AND metric_name='CPU Usage Per Sec') sysmetric_history
WHERE ash.sample_time (+)=sysmetric_history.sample_time
ORDER BY sample_time;

The previous query will only work in 11g and more as it uses the PIVOT keywork, the following will work with 10g.

SELECT
  sysmetric_history.sample_time,
  cpu,
  bcpu,
  DECODE(SIGN((cpu+bcpu)-cpu_ora_consumed), -1, 0, ((cpu+bcpu)-cpu_ora_consumed)) AS cpu_ora_wait,
  scheduler,
  uio,
  sio,
  concurrency,
  application,
  COMMIT,
  configuration,
  administrative,
  network,
  queueing,
  clust,
  other
FROM
  (SELECT
     TRUNC(sample_time,'MI') AS sample_time,
     SUM(DECODE(session_state,'ON CPU',DECODE(session_type,'BACKGROUND',0,1),0))/60 AS cpu,
     SUM(DECODE(session_state,'ON CPU',DECODE(session_type,'BACKGROUND',1,0),0))/60 AS bcpu,
     SUM(DECODE(wait_class,'Scheduler',1,0))/60 AS scheduler,
     SUM(DECODE(wait_class,'User I/O',1,0))/60 AS uio,
     SUM(DECODE(wait_class,'System I/O',1,0))/60 AS sio,
     SUM(DECODE(wait_class,'Concurrency',1,0))/60 AS concurrency,
     SUM(DECODE(wait_class,'Application',1,0))/60 AS application,
     SUM(DECODE(wait_class,'Commit',1,0))/60 AS COMMIT,
     SUM(DECODE(wait_class,'Configuration',1,0))/60 AS configuration,
     SUM(DECODE(wait_class,'Administrative',1,0))/60 AS administrative,
     SUM(DECODE(wait_class,'Network',1,0))/60 AS network,
     SUM(DECODE(wait_class,'Queueing',1,0))/60 AS queueing,
     SUM(DECODE(wait_class,'Cluster',1,0))/60 AS clust,
     SUM(DECODE(wait_class,'Other',1,0))/60 AS other
   FROM v$active_session_history
   WHERE sample_time>sysdate- INTERVAL '1' HOUR
   AND sample_time<=TRUNC(SYSDATE,'MI')
   GROUP BY TRUNC(sample_time,'MI')) ash,
  (SELECT
     TRUNC(begin_time,'MI') AS sample_time,
     VALUE/100 AS cpu_ora_consumed
   FROM v$sysmetric_history
   WHERE GROUP_ID=2
   AND metric_name='CPU Usage Per Sec') sysmetric_history
WHERE ash.sample_time (+)=sysmetric_history.sample_time
ORDER BY sample_time;

Here is a sample graph I generated using SQL Server Reporting Services:

ash

I would like to thank Yannick Jaquier, for providing these queries, you can find his orginal post here

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