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Bad performance in my database & dedlock very urgent

yasser_2
Occasional Advisor

Bad performance in my database & dedlock very urgent

 
yasser
9 REPLIES
Yogeeraj_1
Honored Contributor

Re: Bad performance in my database & dedlock very urgent

hi,

could it be a "resource_manager_plan=SYSTEM_PLAN " related problem?

please post more details about what type of problem you are encountering.

thanks
Yogeeraj
No person was ever honoured for what he received. Honour has been the reward for what he gave (clavin coolidge)
yasser_2
Occasional Advisor

Re: Bad performance in my database & dedlock very urgent

Hit Ratio between 75 to 77
The user they lock many time when start to work in the system when I check the log oracle file give this system do deadlock in this way the system hang
I need to know how I can use the best performances of 2 CPU
What the best parameters
And how I can stop resource the plan of the system in oracle
What is the suitable parameters in kernel UNIX system

yasser
T G Manikandan
Honored Contributor

Re: Bad performance in my database & dedlock very urgent

With regards to your kernel tunables

1.First check what is the value for
dbc_max_pct.

This parameter defines the dynamic buffer cache and takes half the memory be default i.e a value of 50.

For the memory of 1.5GB place the parameter to around 20.
Bring down the dbc_min_pct to 10.

Also
Are you running three or four databases on the same machine.
If only one It looks like these parameters are high


semmni 8200
semmns 16400
semmnu 4096

substantiate that these values are required.


Revert
T G Manikandan
Honored Contributor

Re: Bad performance in my database & dedlock very urgent

With these errors what does the trace file tell u.Get the info from tht trc files and post the info


Thanks
yasser_2
Occasional Advisor

Re: Bad performance in my database & dedlock very urgent

 
yasser
yasser_2
Occasional Advisor

Re: Bad performance in my database & dedlock very urgent

dbc_max_pct = 50
dbc_min_pct to 20
one database
what the good value for that parameters
yasser
T G Manikandan
Honored Contributor

Re: Bad performance in my database & dedlock very urgent

I was talking about these parameters for one database
semmni 8200
semmns 16400
semmnu 4096

It looks high for me
These parameters take away the memory and increase the amount of locked memory.


About the buffer cache values you can bring them down to the value suggested in the previous post.

Just browsed your trace file and looks like the memory is getting exhausted.

I will go the same again and will revert


Thanks
T G Manikandan
Honored Contributor

Re: Bad performance in my database & dedlock very urgent

This is what Oracle recommends

For semmsl,
Set it to 10 plus the largest initsid.ora PROCESSES parameter of an
Oracle database on the system.

For SEMMNS,
Set it to the sum of the PROCESSES parameter for each Oracle database
, plus 2 times the largest PROCESSES value, plus 10
number of Oracle databases.

For example, consider a system that has three Oracle instances with the PROCESSES parameter in their initsid.ora files set to the following values:

ORACLE_SID=A, PROCESSES=100
ORACLE_SID=B, PROCESSES=100
ORACLE_SID=C, PROCESSES=200


The value of SEMMNS is calculated as follows:

SEMMNS = ((A=100) + (B=100)) + ((C=200) * 2) + ((# of instances=3) * 10) = 630


T G Manikandan
Honored Contributor

Re: Bad performance in my database & dedlock very urgent

Also check the attachment