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Re: Monitor contention

From: Greg Rahn <greg_at_structureddata.org>
Date: Tue, 15 May 2007 10:46:42 -0700
Message-ID: <4649F202.1050107@structureddata.org>


That makes much more sense.

In your original post you stated:
Performance papers suggest tuning the index storage parameters to allow for fewer entries per block so that the nodes are not all going after the same block.

Your contention probably is from a right-growing index if you are using a sequence as the value for the key column. A right-growing index is a scalability hurdle that is exacerbated in a RAC environment. The more nodes, the more contention. Often times this is best dealt with by using hash partitioning. This makes a single "hot" index into several "warm" index partitions. I think that using hash partitioning would yield better results then messing with storage parameters, but of course, YMMV.

Regards,

Greg Rahn
http://structureddata.org

> This is a case of me being as clear as mud. I mean we set a flag in the
> application that turn off inserts to the logging table.
>
> On 5/15/07, *Greg Rahn* < greg_at_structureddata.org
> <mailto:greg_at_structureddata.org>> wrote:
>
> I think this may be a case of correlation without causation. Changing
> an index from logging to nologging would have no affect on conventional
> inserts.
>
> To quote the documentation:
> http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14231/tables.htm#sthref2199
> <quote>
> The NOLOGGING clause also specifies that subsequent direct loads using
> SQL*Loader and direct load INSERT operations are not logged. Subsequent
> DML statements (UPDATE, DELETE, and conventional path insert) are
> unaffected by the NOLOGGING attribute of the table and generate redo.
> </quote>
>
> Regards,
>
> Greg Rahn
> http://structureddata.org
>
>

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Received on Tue May 15 2007 - 12:46:42 CDT

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