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Don Burleson Blog 







dba_hist_service_wait_class Tips

Oracle Database Tips by Donald BurlesonNovember 5, 2015

Question:  What does the AWR table dba_hist_service_wait_class do?  How can I use dba_hist_service_wait_class to see system wait information?

Answer:  The script below uses dba_hist_service_wait_class to display the waits by day for a tiny Oracle system.  Here is another service wait class script to display waits by day using the AWR dba_hist_service_wait_class table:


col c1 heading 'end|time'    format a10
col c2 heading 'wait|class'  format a20
col c3 heading 'time|waited' format 999,999,999,999

break on c1 skip 2

   trunc(end_interval_time) c1,
   wait_class c2,
   sum(time_waited) c3
   dba_hist_snapshot USING(snap_id)
group by
order by
c3 desc;


Here is a sample of the output:


end        wait                 time
time       class                waited
---------- -------------------- ----------------
31-OCT-12  Idle                  2,569,604,134
           System I/O               21,125,983
           Other                       134,514
           User I/O                    126,006
           Concurrency                  98,622
           Commit                       24,102
           Scheduler                     3,458
           Configuration                 1,273
           Application                     140
           Network                         126

01-NOV-12  Idle                  3,202,677,185
           System I/O               22,725,490
           Other                       138,425
           User I/O                    119,588
           Concurrency                 115,050
           Commit                       28,105
           Configuration                 3,991
           Scheduler                     3,211
           Application                     130
           Network                         117


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