Re: High Redo Copy Contention

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Tue, 3 Apr 2001 21:09:48 +0100
Message-ID: <986328842.3773.0.nnrp-09.9e984b29@news.demon.co.uk>

Quote:

My doctor told me that the ratio of fat in my diet was too high - but I fixed it by drinking two pints of coca-cola with every meal.

end-quote.

Look at the actual numbers of redo copy latch gets and misses (as opposed to immediate gets and misses). There will be hardly any. Redo Copy Latch misses are expected, and unless you have a truly bizarre problem can be ignored.

--
Jonathan Lewis
Yet another Oracle-related web site:  http://www.jlcomp.demon.co.uk

Practical Oracle 8i:  Building Efficient Databases
Publishers:  Addison-Wesley

Reviews at: http://www.jlcomp.demon.co.uk/book_rev.html



Anurag Minocha wrote in message ...


>Hi,

>

>I am getting a High redo copy contention even after increasing the

>log_small_entry_max_size from 80 to 200.  In fact I had a average redo size

>of 253 before increasing the log_small_entry_max_size parameter. yesterday

>after running the utlbstat/utlestat files I noticed that my average redo

>size (redo size/redo entries) has increased to 972.Why has this increased

>and how do I reduce the redo copy contention.

>

>PLEASE HELP.

>

>

>ON 03/27/2001

>-------------

>  Tablespace    Miss Ratio

>--------------- ----------

>redo allocation .095841187

>redo copy       95.2702703

>redo writing    .048722391

>row cache objec .000724082

>

>Initialization Parameters

>--------------------------

>

>log_archive_buffer_size        127

>log_archive_buffers            4

>log_archive_min_succeed_dest   1

>log_archive_start              FALSE

>log_block_checksum             FALSE

>log_buffer                     102400

>log_checkpoint_interval        8000

>log_checkpoint_timeout         0

>log_checkpoints_to_alert       FALSE

>log_file_name_convert

>log_files                      255

>log_simultaneous_copies        4

>log_small_entry_max_size       80

>

>

>ON 04/03/2001

>-------------

>

>  Tablespace    Miss Ratio

>--------------- ----------

>

>redo allocation .093745374

>

>redo copy       98.1246308

>

>redo writing    .019016566

>

>row cache objec .002990484

>

>Initialization Parameters

>--------------------------

>

>log_archive_buffer_size        127

>log_archive_buffers            4

>log_archive_min_succeed_dest   1

>log_archive_start              FALSE

>log_block_checksum             FALSE

>log_buffer                     102400

>log_checkpoint_interval        8000

>log_checkpoint_timeout         0

>log_checkpoints_to_alert       FALSE

>log_file_name_convert

>log_files                      255

>log_simultaneous_copies        4

>log_small_entry_max_size       200

>

>

>Thanks

>Anurag

>

>--

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Received on Tue Apr 03 2001 - 15:09:48 CDT