Operating System - HP-UX
1748185 Members
4157 Online
108759 Solutions
New Discussion юеВ

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

 
SOLVED
Go to solution
Fred Ruffet
Honored Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

I can not certify this, and maybe someone may say it's right or wrong, but here is what I saw when working on the subject :
When issuing dd with different block sizes, and monitoring with glance, I can see that transfered size divided by IO count is equal to dd's bs, while bs inferior to 256KB. If bs is larger than 256KB, IOs seems broken and are always 256KB large.
I never managed to find a parameter to increase that size. scsi_maxphys default value is set to 1MB as a default, so it may not be the blocking factor.
Note that my tests were only for reads.

Regards,

Fred
--

"Reality is just a point of view." (P. K. D.)
Eric Antunes
Honored Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

Hi Fred,

From what I understood scsi_maxphys is the overall limit (must not be changed) but there is a hardware limit, depending on the device and its associated drivers.

To you use a different value than the default 1 (for 1 CPU) for spin_count?

Regards,

Eric Antunes
Each and every day is a good day to learn.
renarios
Trusted Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

Hi Eric,

Here's a script which tells you a lot about tunable parameters. Also physical reads and writes. Read it carefully, execute it several times at the same time of the day and try to change the parameters positively.
you can always use Oracle Enterprise Manager to view things graphically.

Cheers,

Renarios
Nothing is more successfull as failure
Eric Antunes
Honored Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

Hi renarios,

You missed the script...

Regards,

Eric
Each and every day is a good day to learn.
Fred Ruffet
Honored Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

Eric,

What is spin_count ?

Renarios,

Oracle version is 8.0.5. OEM of such old versions (DBA studio) is rather buggy and less complete than nowadays. If he uses last OEM version, I doubt that parameters descriptions are accurate.

Regards,

Fred
--

"Reality is just a point of view." (P. K. D.)
Eric Antunes
Honored Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

Fred,

spin_count is "Amount to spin waiting for a latch". But I think it is only usefull to be set with a different value than de default (1) for multiprocessor systems...
Each and every day is a good day to learn.
renarios
Trusted Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

Sorry Eric,

Here's take two:

Cheers,

Renarios
Nothing is more successfull as failure
Fred Ruffet
Honored Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

Sorry for the question, but this parameter has been obsoleted in 8i. It's been a long time since I use it, and I don't remembre about its setting... :-/ (Have you read Note 30832.1 in metalink ?)

Regards,

Fred
--

"Reality is just a point of view." (P. K. D.)
Eric Antunes
Honored Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

Thanks Renarios!

Fred,

yes I've readed it. I'm reviewing all init.ora parameters that are not derived...

Best Regards,

Eric Antunes
Each and every day is a good day to learn.
Eric Antunes
Honored Contributor

Re: Any feedback for init.ora parameter discrete_transaction_enabled?

I'm closing this thread.

Thanks to all!
Each and every day is a good day to learn.