Re: redo logs and IO please advise

Excellent point!

I think I will have a screen to track the information in the LogHistory as well.

Is the table the same name in Oracle versions 7 - 8i?

On Sat, 31 Mar 2001 20:44:10 +0100, "Dave Francis" <d_a_francis_at_yahoo.co.uk> wrote:

>So long as your redo log files change about every half hour, according to
>standard guidelines, they`re correctly saved. Bear in mind that batch jobs -
>if you`re running `em during the day - will probably produce more redo log
>activity.
>
>Redo log statistics don`t really matter - beyond reasonable limits. So long
>as they`re not writing excessively - in which case, size `em
>bigger........... remember the point that they`re only used in instance
>recovery. So they`ve got to be there, that`s all !!! And - not tying your
>system IO up excessively.
>
>Dave
>
>Piet de Visser wrote in message <99vpqf$1377$1_at_buty.wanadoo.nl>...
>>Here is my script (ora8 version) m
>>Obvious remarks :
>> - depending on disk-system, usage etc... have seen upto 10000.0 kb/s on
>>fiberchannel disks.
>> - redo is mostly the hottest disk in a oltp or batch system, and almost
>>always a hit with tuning.
>>
>>HTH
>>
>>doc
>> scan04.sql
>> Transaction volume for log switches.
>> - less then 1000 seconds per switch is "fast",
>> consider larger logfiles
>> - Last column > 100.00 is considered "high volume"
>> examine batches, try to spread (batch) load over time
>>#
>>
>>column sec format 9999
>>column ch_per_sec format 99999.999
>>column kb_per_sec format 99999.999
>>
>>select
>> to_char ( lh2.first_time, 'DD-MON-YY HH24:MI:SS' ) switch
>>, TO_NUMBER ( lh2.first_time
>> - lh1.first_time
>> ) * 3600 * 24 seconds
>>, ( l.bytes / 1024 )
>> / ( TO_NUMBER ( lh2.first_time
>> - lh1.first_time
>> ) * 3600 * 24
>> ) kb_per_sec
>>from v$log_history lh1
>>, v$log_history lh2
>>, v$log l
>>where lh1.sequence# = lh2.sequence# -1
>>and TO_NUMBER ( lh2.first_time
>> - lh1.first_time
>> ) * 3600 * 24 > 0 /* min. 60 avoids hot bck peaks */
>>and l.status = 'CURRENT' /* assume all groups equal file-sizes */
>>and lh1.sequence# > l.sequence# - 500
>>order by lh1.sequence#
>>/
>>
>>
>>--- end of script
>>"Kev.-" <java2e_at_yahoo.com> wrote in message
>>news:3ac2a0cd.329368987_at_ns1.nothingbutnet.net...
>>> Hello All,
>>>
>>> Now that I know the right question to ask here it goes. What table
>>> can you query to get the IO (physical reads and writes) that they are
>>> producing?
>>>
>>> For example when I query v$filestat I am able to get reads and writes
>>> that the file has produced since the oracle server was booted as the
>>> values keep incrementing until re-booted/ shutdown-re-started, etc...
>>>
>>> How can I get these same values for the redo logs. I have looked the
>>> the v$log, v$logfile but there is nothing there.
>>>
>>> Thanks,
>>>
>>> Kev.-
>>
>>
>
>
Received on Mon Apr 02 2001 - 17:47:37 CDT