Re: storing lobs as secure files - any gotchas?
From: Tanel Poder <tanel_at_tanelpoder.com>
Date: Thu, 28 Feb 2013 01:10:02 +0200
Message-ID: <CAMHX9J+6MvCOauoM3NzusT8YvSwVHZHgN=Dt_TbBoHtG+q=0zA_at_mail.gmail.com>
I recommend you read this too if you expect plenty of update activity on your securefile LOB items:
*Securefiles DMLs cause high 'buffer busy waits' & 'enq: TX - contention' wait events leading to whole database performance degradation [ID 1532311.1]
As a workaround (until the change gets built in to 11.2.0.4 and 12c) you need to set *_securefiles_concurrency_estimate = 50 **before* creating the tables.
Date: Thu, 28 Feb 2013 01:10:02 +0200
Message-ID: <CAMHX9J+6MvCOauoM3NzusT8YvSwVHZHgN=Dt_TbBoHtG+q=0zA_at_mail.gmail.com>
I recommend you read this too if you expect plenty of update activity on your securefile LOB items:
*Securefiles DMLs cause high 'buffer busy waits' & 'enq: TX - contention' wait events leading to whole database performance degradation [ID 1532311.1]
* * *
As a workaround (until the change gets built in to 11.2.0.4 and 12c) you need to set *_securefiles_concurrency_estimate = 50 **before* creating the tables.
-- *Tanel Poder* Enkitec (The Exadata Experts) Training <http://blog.tanelpoder.com/seminar/> | Troubleshooting<http://blog.tanelpoder.com/> | Exadata<http://www.amazon.com/Expert-Oracle-Exadata-Apress/dp/1430233923> | Voicee App <http://voic.ee/> On Wed, Feb 27, 2013 at 2:20 PM, orcl <orcl_at_comcast.net> wrote:Received on Thu Feb 28 2013 - 00:10:02 CET
> Hi all, 11.2 on Linux. I have a 300g table with 80k rows that has 3
> CLOB columns. Most of the records are similar size - some are very large
> . Im planning to
>
> Partition the table and use store as secure file (deduplicate compress)
>
> Are there any issues (bugs etc) with using the deduplicate or compress?
> any positive experience to share? Other suggestions to do it better?
>
> Ill check on mos for bugs - but wanted to run the question here.
>
>
> also, what is the difference of creating the partition table - then
> doing direct path (nologging) insert as one big load, then build the
> indexes as opposed to exchanging one partition at a time. In this case
> my partitions are on year and I have 3 years to load.
>
> Thanks!
> Bob
>
> --
> "Oracle error messages being what they are, do not highlight the correct
> cause of fault, but will identify some other error located close to where
> the real fault lies."
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>
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