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> Big debate around cpu used by non active session, cpu use of inactive session
cloporte
post Oct 11 2017, 12:01 PM
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Hello,

we are having a big debate here about the cpu use of non active session,

our vendor have for some reasons change the behavior of its webserver and now the first thing it does when sarting the web instance

is that it will connect with around 1000 sessions to the oracle database waiting for some users to work and will never release those connections until the web server is restarted (every night)

We have noticed since they have implemented that new version a higher cpu usage, even if we don't see much activity regarding active sessions, if i do on the unix

a sar 1 5, i see only few cpu idle and if i do this

ps -e -o pcpu,pid,user,tty,args |sort -n -k 1 -r| head -1000

i see in that list many SPID from the supposed inactive sessions , they are not using very much cpu 1% or less of a core , but if you do multiplicate it by 1000 guess what ??

one of my colleagues told me even if the sessions is tagged as inactive it is using very little cpu to continue talking to the db .

i cannot find much documentation about this .

thanks in advance !
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burleson
post Oct 11 2017, 03:09 PM
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Hi Cloporte, and welcome to the forum!

It is very common for an app server to pre-spawn connections to Oracle!

Even an inactive session will consume CPU, as it polls the database to verify connectivity.

It should not be much, see my notes here:

http://www.dba-oracle.com/t_high_cpu.htm


--------------------
Hope this helps . . .

Donald K. Burleson
Oracle Press author
Author of Oracle Tuning: The Definitive Reference
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cloporte
post Oct 12 2017, 12:43 AM
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Helllo,

i have already seen your post,

i know this is very little consumption but since it's over 1000 sessions, i suspect it will have an impact on the cpu at the end .

Thanks a lot to confirm this !
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