| Contention on data blocks [message #480287] |
Fri, 22 October 2010 04:55  |
jimit_shaili
Messages: 237
Registered: June 2006
Location: India, Ahmedabad
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Senior Member |
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Dear Friends,
We are suffering from very bad application response for last few days,
when i try to check and drill down, where the actual contention is?
I came to know that there may be contention on data blocks,
which may be a prime reason for degraded performance. Herewith i'm pasting my
actual stats of gathered from v$waitstat.
I gone through some of asktom docs and find that there may be a problem with
freelist or segment space management.
My data tablespace is segment space management = Manual.
My main question is
1) Should i need to increase freelist value (Right now my value is 1)
2) Or i have to move on segment space management = auto
SQL> select * from v$waitstat;
CLASS COUNT TIME
------------------ ---------- ----------
data block 2022 4052
sort block 0 0
save undo block 0 0
segment header 1 1
save undo header 0 0
free list 0 0
extent map 0 0
1st level bmb 0 0
2nd level bmb 0 0
3rd level bmb 0 0
bitmap block 0 0
bitmap index block 0 0
file header block 0 0
unused 0 0
system undo header 0 0
system undo block 0 0
undo header 6 0
undo block 0 0
18 rows selected.
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| Re: Contention on data blocks [message #480344 is a reply to message #480287] |
Fri, 22 October 2010 09:11  |
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BlackSwan
Messages: 26766
Registered: January 2009
Location: SoCal
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Senior Member |
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While some many find the posted results as interesting.
I contend that NOTHING meaningful can be concluded from these number.
In My Opinion, you need to identify the SQL that are deemed to be "slow" &
then run SQL_TRACE=TRUE for those sessions to see where time is being spent
[Updated on: Fri, 22 October 2010 09:18] Report message to a moderator |
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