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Pct_free
Hi,
quick question.
In a data warehouse DB, If i know that in any given table only insert operations happens, is it feasible to set pctfree to 0 to save some storage?
I know depends on block size and row length there is a chance of row chaining. I am monitoring the table regularly. Also, want to see the comments about the same here.
Thanks,
Last edited by vnktummala; 11-11-2010 at 02:08 AM.
Reason: typo
Vijay Tummala
Try hard to get what you like OR you will be forced to like what you get.
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Would work for updates too as long as changed value is no longer than the original. Seems like that setting wouldn't cause any problems.
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Vijay Tummala
Try hard to get what you like OR you will be forced to like what you get.
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Originally Posted by vnktummala
In a data warehouse DB, If i know that in any given table only insert operations happens, is it feasible to set pctfree to 0 to save some storage?
I know depends on block size and row length there is a chance of row chaining. I am monitoring the table regularly. Also, want to see the comments about the same here.
This is a very good analysis and I agree with Stecal comment.
Building on such comment as well as in original analysis I would like to add that - in my experience - setting pct_free to values in between 5 and 10 brings to the table the best of both world, space saving and low percentaje of chained/migrated rows.
Having said that, I've also seen DWH tables getting new columns as well as getting "special" update processes which caused horrendous results on the chained/migrated rows department.
Pablo (Paul) Berzukov
Author of Understanding Database Administration available at amazon and other bookstores.
Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.
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Vijay Tummala
Try hard to get what you like OR you will be forced to like what you get.
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