Re: Statspack reliability

Its probably internal 4 byte integers that wrap around. All the X$ tables on which the V$ views are build really are simple integers internally, but they are externalised to Oracle numbers without any check for wrapping.

/Bjørn.

Stephane Paquette wrote:

>Hi all,
>
>We're running statspack each hour on all the production instances, Oracle
>8.1.7.2 AIX 4.3.3
>Last week, on one database, we had 3 numbers that were 100000 times bigger
>than usual.
>
>2 were about df file sequential read that were over 100000 times the
>average.
>Top 5 Wait Events
>~~~~~~~~~~~~~~~~~ Wait %
>Total
>Event Waits Time (cs) Wt
>Time
>-------------------------------------------- ------------ ------------ -----
>--
>db file sequential read 126,541 ############
>99.99
>db file scattered read 491,345 154,658
>.01
>rdbms ipc reply 2,983 24,293
>.00
>library cache lock 367 7,197
>.00
>db file parallel write 9,551 5,981
>.00
>
>Top 5 Wait Events
>~~~~~~~~~~~~~~~~~ Wait %
>Total
>Event Waits Time (cs) Wt
>Time
>-------------------------------------------- ------------ ------------ -----
>--
>db file sequential read 262,496 ############
>99.99
>db file scattered read 144,216 65,771
>.00
>rdbms ipc reply 1,788 14,919
>.00
>direct path read 17,478 9,586
>.00
>db file parallel read 1,701 4,465
>.00
>
>The third wait is
>Top 5 Wait Events
>~~~~~~~~~~~~~~~~~ Wait %
>Total
>Event Waits Time (cs) Wt
>Time
>-------------------------------------------- ------------ ------------ -----
>--
>SQL*Net more data to client 3,041,574 ############
>99.99
>db file scattered read 79,465 67,945
>.00
>db file sequential read 56,900 50,106
>.00
>rdbms ipc reply 497 3,530
>.00
>db file parallel write 1,224 971
>.00
>
>Here is the wait time per snap_id from the statpack tables
> 5693 1882138496 db file sequential read
> 5692 22114 db file sequential read
>
> 5819 3803314081 db file sequential read
> 5818 1892117288 db file sequential read
>
> 5765 1900925255 SQL*Net more data to client
> 5764 66883 SQL*Net more data to client
>
>I checked on the unix side.
>For the first Oracle wait I had a spike in the IO performance graph (disk
>read/write per sec) but it was for writing. For the second and third Oracle
>wait, I had nothing on the unix side.
>
>
>
>So is that a glitch in statspack or where else can I look ?
>
>
>
>Stephane Paquette
>Administrateur de bases de donnees
>Database Administrator
>Standard Life
>www.standardlife.ca
>Tel. (514) 925-7187
>stephane.paquette_at_standardlife.ca <mailto:stephane.paquette_at_standardlife.ca>
>
>
>
>

-- 
Bjørn Engsig, Miracle A/S
Member of Oak Table Network <http://www.oaktable.net>
Bjorn.Engsig@MiracleAS.dk - http://MiracleAS.dk


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