Re: Calculations in maximizing rows per block

From: Rich J <>
Date: Tue, 15 Aug 2017 09:48:40 -0500
Message-ID: <>

On 2017/08/15 08:05, Tim Gorman wrote:

> Not sure if your table of 268 columns might be sparsely-populated or not, but if the possibility exists, you might be interested in verifying using the "carl.sql" procedure from this page HERE [1] and referencing this presentation HERE [2] and this white paper HERE [3]. CARL (calculate average row length) will attempt to recalculate how you can optimize your AVG_ROW_LEN by re-organizing the table so that all non-null columns are first in each row, leaving any null columns to trail. Along the way, it will also attempt to calculate AVG_ROW_LEN for the present organization. In order for CARL to work properly, it is best to have analyzed the table for column-level statistics. The presentation and white paper will also have passing mention of intra-block chaining, as well as other types of chaining/row-migration.
> With more than 255 columns, you can't take advantage of BASIC or OLTP compression, but any version of Oracle and any wide table can take advantage of "trailing NULLCOLS" compression.
> Hope this helps...

I opened your whitepaper first...this could take awhile, but I like where it's going. :)



[2] [3]
Received on Tue Aug 15 2017 - 16:48:40 CEST

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