Re: Archive Log Size
From: Martin Klier - Performing Databases GmbH <martin.klier_at_performing-db.com>
Date: Thu, 14 Jan 2021 13:34:06 +0100 (CET)
Message-ID: <516760064.10166.1610627646085.JavaMail.zimbra_at_performing-db.com>
Date: Thu, 14 Jan 2021 13:34:06 +0100 (CET)
Message-ID: <516760064.10166.1610627646085.JavaMail.zimbra_at_performing-db.com>
Jonathan,
that's awesome. I already wild-guessed in that direction (something like the relation of private strands to the size of the log buffer), especially since we have a massively asynchronous load / semi loaded system. But this explanation is very plausible and good.
Thank you, also for the quick response. Martin
-- Martin Klier // Performing Databases GmbH Managing Partner // Senior DB Consultant Oracle ACE Director martin.klier_at_performing-db.com // https://www.performing-databases.com > Von: "Jonathan Lewis" <jlewisoracle_at_gmail.com> > An: "Oracle-L Freelists" <oracle-l_at_freelists.org> > Gesendet: Mittwoch, 13. Januar 2021 17:30:46 > Betreff: Re: Archive Log Size > This might be highly relevant: > [ > https://www.red-gate.com/simple-talk/sql/oracle/are-your-oracle-archived-log-files-much-too-small/ > | > https://www.red-gate.com/simple-talk/sql/oracle/are-your-oracle-archived-log-files-much-too-small/ > ] > Regards > Jonathan Lewis > On Wed, 13 Jan 2021 at 16:11, Martin Klier - Performing Databases GmbH < [ > mailto:martin.klier_at_performing-db.com | martin.klier_at_performing-db.com ] > > wrote:Received on Thu Jan 14 2021 - 13:34:06 CET
>> Hi folks,
>> I observe a behaviour I can't explain:
>> Platform: Windows
>> Oracle Version: 12.1.0.2
>> Online Redo Log Size: initially 300MB, later 1GB
>> Sometimes the archived redo logs get as big as the redo log size is, but that's
>> rarely the case. Usually, I end up with less than 100MB. Why?
>> Whenever I hit ARCHIVE_LAG_TARGET, it's easy to explain, why they are smaller.
>> Same during backups or when I switch manually. But why during normal
>> operations, even high redo log pressure (log switch every 30sec), IMO the redo
>> logs (and thus, the archives) should be pretty full, isn't it?
>> The ratio is about 100MB for 300GB Redo Logs, and about 800MB for 1GB Redo Log
>> size.
>> Any ideas?
>> Thanks a lot
>> Martin
>> --
>> Martin Klier // Performing Databases GmbH
>> Managing Partner // Senior DB Consultant
>> Oracle ACE Director
>> [ mailto:martin.klier_at_performing-db.com | martin.klier_at_performing-db.com ] // [
>> https://www.performing-databases.com/ | https://www.performing-databases.com ]
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