RE: Check Point Interval Question

Thanks alot jared,

I just want to know if I change my redo log size to 10000 K, do I have to change checkpoint_interval to 20000 or still 10000 doesn't affect.

Thanks alot

-----Original Message-----
Sent: Wednesday, November 13, 2002 8:28 PM To: Multiple recipients of list ORACLE-L

Hamid,

Is there perhaps a reason given for that setting?

The setting determines how often a checkpoint will be performed based on the number of redo log blocks.

>From the FM:

LOG_CHECKPOINT_INTERVAL specifies the frequency of checkpoints in terms of the number of redo log file blocks that can exist between an incremental checkpoint and the last block written to the redo log. This number refers to

physical operating system blocks, not database blocks.

On Solaris, that's 512 bytes per block.

see:
http://www.ixora.com.au/notes/log_block_size.htm

With a value of 10000, the setting had no effect on your log file of 4m, since
a 4 meg file consists of 8192 512 byte blocks.

Similarly, a setting of 9999999 will not cause any extra checkpoints to be written between log switches. A 20 meg log file has 40960 512 byte blocks.

Setting LOG_CHECKPOINT_INTERVAL = 0 would have the same effect in both cases.

Jared

On Wednesday 13 November 2002 09:54, Hamid Alavi wrote:
> Dennis,
>
> Here it is in the oracle performance tuning (Tip's & Techniques) page
735
> suggested value for LOG_CHECKPOINT_INTERVAL = 9999999.
>
> My oracle version is 8.1.7.4 on sun solaris, 2.8, and I have some CPU
> problem, My thought is may be some checkpoint problem so, I have decided
to
> increase the size of my Redo log from 4M to 20M and change the
> log_checkpoint_interval from 10000 to 9999999 but I don't know what's the
> best setting for these numbers.
>
>
> -----Original Message-----
> Sent: Wednesday, November 13, 2002 9:16 AM
> To: Multiple recipients of list ORACLE-L
>
>
> Hamid - Which parameter to use depends on your Oracle version. If it is
9i,
> use FAST_START_MTTR_TARGET. In 8i, use LOG_CHECKPOINT_TIMEOUT. Did your
> tuning manual explain why you should set it to 9999999? That seems a
little
> strange. Basically shorter checkpoint queue lengths will shorten your
> recovery times, but too short a queue length may hamper performance, so it
> is a tradeoff. What are your tradeoff criteria?
>
> Dennis Williams
> DBA, 40%OCP
> Lifetouch, Inc.
> dwilliams_at_lifetouch.com
>
>
> -----Original Message-----
> Sent: Wednesday, November 13, 2002 10:39 AM
> To: Multiple recipients of list ORACLE-L
>
>
> Hi List,
>
> I have a question regarding check_point_interval. In my setting
> log_checkpoint_interval = 10000 & log_checkpoint_timeout = 1800 , I
findout
> in the tuning manual which I have to change thelog_checkpoint_interval =
> 9999999 but nothing regarding the log_checkpoint_timeout, when I change
the
> interval to 9999999 do I have to change the checkpoint_timeout too, or
> what's the best setting for these two numbers.
> I got confued, some where in the manual they are talking about to set
> timeout to zero some where else diffrent setting, I realy appreciate if
> some body give me a pratical Idea.
>
> Thanks for your help.
>
>
>
>
> Hamid Alavi
> Office 818 737-0526
> Cell 818 416-5095
>
>
>
>
>
>
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======================= Confidentiality Statement ======================= 
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intended only for the use of the individual or entity to which it is 
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and exempt from disclosure under applicable law.  If you have received 
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-- 
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-- 
Author: Hamid Alavi
  INET: hamid.alavi_at_quovadx.com

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