wait event for switch log file command

[hrishy]

Hi Marist

why would u look for smaller time slices in the statspack report.The statspack report is taken in a interval of 15 minutes..

regards
Hrishy

[marist89]

I am guessing that waiting on a logswitch is happening during that 15 minute window with not a lot of other activity going on. Therefore, the time spend waiting for a log switch may be high in comparison to other waits going on.

A smaller window will let you see what is happening between log switches. If you got still get high logswitch waits when no logswitch occurs, there is something else going on.

[DaPi]

Originally posted by hrishy
I dont have exact number but in the top 5 wait events .

BUT YOU DO! It's all there in the statspack, e.g.:

Top 5 Wait Events
~~~~~~~~~~~~~~~~~                                             Wait     % Total
Event                                               Waits  Time (cs)   Wt Time
-------------------------------------------- ------------ ------------ -------
db file sequential read                             9,747        7,168   45.34
control file parallel write                         1,250        2,012   12.73
file open                                             441        1,379    8.72
enqueue                                                24          946    5.98
log file sync                                         557          715    4.52
          -------------------------------------------------------------



Wait Events for DB: PROD  Instance: prod  Snaps: 992 -993
-> cs - centisecond -  100th of a second
-> ms - millisecond - 1000th of a second
-> ordered by wait time desc, waits desc (idle events last)

                                                                    Avg
                                                     Total Wait    wait  Waits
Event                               Waits   Timeouts  Time (cs)    (ms)   /txn
---------------------------- ------------ ---------- ----------- ------ ------
db file sequential read             9,747          0       7,168      7    3.8
control file parallel write         1,250          0       2,012     16    0.5
file open                             441          0       1,379     31    0.2
enqueue                                24          0         946    394    0.0
log file sync                         557          1         715     13    0.2
log file parallel write               644          0         538      8    0.2
control file sequential read        6,004          0         514      1    2.3 

[DaPi]

Originally posted by marist89
Therefore, the time spend waiting for a log switch may be high in comparison to other waits going on.

Jeff, I think this could be one of those cases where a ratio (58% of waits are due to X) is misleading. The real question is: how long are my users waiting because of X? Is it milliseconds, seconds, minutes, hours?

[marist89]

Originally posted by DaPi
Jeff, I think this could be one of those cases where a ratio (58% of waits are due to X) is misleading. The real question is: how long are my users waiting because of X? Is it milliseconds, seconds, minutes, hours?

True, could be.

[hrishy]

Hi Dapi

:-) Well i dont have acesses to raw data like that.Just graphs and pie charts :-)

regards
Hrishy

[DaPi]

Originally posted by hrishy
Well i dont have acesses to raw data like that.Just graphs and pie charts

Aghhhhh! You've been got at by the marketeers! The "raw" data come from the standard "spreport".

P.S. how do you get the fancy stuff? I might want to impress my boss . . . .

[hrishy]

Hi Dapi

There is a custom program written that will graph all the details to me with fancy HTML using applets etc..no acessses to raw data :-)

i guess we can easily write sucha prog using php and GD library :-)

regards
Hrishy

[DaPi]

Hi Hrishy, Yet another GUI that stops you seeing the truth! If your "customisers" can't show you the TIME waited, it's time to send in Mr.Hanky (or Donald von Rumsfeld).

[hrishy]

Originally posted by DaPi
Hi Hrishy, Yet another GUI that stops you seeing the truth! If your "customisers" can't show you the TIME waited, it's time to send in Mr.Hanky (or Donald von Rumsfeld).

Hi Dapi

hehe :-)

regards
Hrishy