Re: Row Chaining

Hi Jerry,

I worked with a third party application last year where the canned table definitions were so bad that I could reorganize the tables every night to shrink them down to one extent each and by the end of the day some tables had as many as 17 extents!

Needless to say, the table building code was generated by a program which I couldn't get to and the vendor wouldn't change.

You can avoid these problems by using STORAGE clauses in your table create statements. Make the initial extent large enough to handle the expected normal volume and the next extent large enough so that one additional extent will hold all but the biggest tables. Also look at altering the PCTFREE value to leave enough space to accommodate all of the data that will be entered AFTER THE TABLE IS CREATED. Finally, if your applications entail the initial creation of a subset of each row and the row is filled in later use CHAR instead of VARCHAR or VARCHAR2 in order to reserve the space up front.

Regards

Jerry

Jerry Veno wrote:
>
> I'd like to hear opinions as to when row chaining is a problem and when
> I should be concerned. The books I've looked at say if any chaining at
> all occurs to fix it, but in real life, I don't think that's feasible.
> Any ideas?

--

Jerry Gitomer         	ICT Group
jgitomer_at_ictgroup.com	Langhorne PA
jgitomer_at_yahoo.com 	Opinions are mine not those of ICT Group