Re: intermittent very high waits in LGWR on Linux?

From: bugbear <bugbear_at_trim_papermule.co.uk_trim>
Date: Fri, 01 Jul 2005 15:54:02 +0100
Message-ID: <42c5590b$0$2048$ed2e19e4@ptn-nntp-reader04.plus.net>

DA Morgan wrote:
> bugbear wrote:

<<trace information snipped>>

>>
>> Oracle is making heavy use of neither CPU nor IO!!!!
>> (and neither is anything else...)
>> It appears that the "log file sync waits" I'm seeing are more
>> like sleeps(). It ain't even tryin'.
>>
>> Since the LGWR is a separate process, I start to (again) suspect Linux
>> scheduling.
>>
>>     BugBear

>
>
> I'm seeing something very similar on a system running 10.1.0.3 during a
> CREATE TABLE AS ....
Ah hah! It's not just me. I was gettin' paranoid, you know ;-)

>
> Increase the size of log buffers (possibly a lot).
> How many log files? What size? How many groups? members?

As per Noon's advice:

> and now add these:
> log_buffer=1048576
> log_checkpoint_interval=10000
> db_writer_processes=2

    BugBear Received on Fri Jul 01 2005 - 09:54:02 CDT