Re: Redo Log Problem

Three redo log groups is usually insufficient. I start out with a minimum of 4. As per previous discussions on this group your redo log buffer is way too big. The buffer is written to disk whenever one third of it is 'dirty'. This means you are creating a problem on your redo log drives, as you a writing 3300k to disk at a time.
The maximum redo log buffer is supposedly 1M and you have a buffer that is 10 times as big.
Probably you will see 'checkpoint not complete' messages when you reduce the size of your buffer, in that case increase the size and the number of your online redolog files.

What are you exactly doing with this database that a redolog buffer of 10M still creates buffer space requests?

Hth,

Sybrand Bakker, Oracle DBA

"Scott W. Patterson" <swpatterson_at_mindspring.com> wrote in message news:3A3914F0.DE0B5AD1_at_mindspring.com...
> I am running a script from the Oracle on NT website called CheckTune.
> The results of the queries are a follows below....
>
> Current Date and Time: 12/14/2000 12:18:40
> Database name: par_22
> Measurement Goal Value Action
> ------------------------------ ------ -----------
> -------------------------------------------------
> Library cache hit percent >=0.99 1.00 OK
> Dictionary cache hit percent >=0.90 0.93 OK
> Buffer cache hit percent >=0.90 0.96 OK
> Sort area hit percent >=0.90 1.00 OK
> Redo Log space requests =0
> 180 Increase the LOG_BUFFER in INIT.ORA
> "
> Examine Redo Log size
> "
> Examine number of Redo Log groups
> -- Current value: log_buffer = 10240000
> -- Current value: redo log size = 5242880
> -- Current value: # of redo log groups = 3
> Enqueue waits =0 0 OK
> Checkpoints not completed <=1 0 OK
> Rollback contention ratio <=0.01 0.00 OK
> Redo allocation latch miss (W) <=0.01 0.00 OK
> Redo allocation latch miss (I) <=0.01 0.00 OK
> Redo copy latch miss (WTW) <=0.01 0.90
> Increase LOG_SIMULTANEOUS_COPIES 2xCPU in INIT.ORA
> -- Current value: log_simultaneous_copies = 4
> -- Current value: log_small_entry_max_size = 0
> Redo copy latch miss (Immed) <=0.01 0.00 OK
> Freelist contention ratio <=0.01 0.00 OK
> Input truncated to 15 characters
>
>
> I am trying to understand what to do about the the Redo Log Space
> Requests problem ...
> I have increased the size of the log files, the log buffer, and the
> number of groups (3 groups, with two members each -size 5mg)
> I set the log buffer to twice the size of a redo log file - at least I
> think so..
> The log files are on a hardware - RAID 1 disk . I speculate that since
> all the log files are on this same disk is the reason I am getting this
> problem.
>
> Any suggestions????
>
> Thanks,
>
> Scott Patterson
> Patterson Advertising Reports
>
Received on Thu Dec 14 2000 - 13:08:14 CST