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Keep dataset option. Reading large tables.

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Occasional Contributor
Posts: 10

Keep dataset option. Reading large tables.

Hi.

Will be there or not any difference in perfomance in following situation.

I have two tables.
Table A has three columns and 10G in size. I need data from two columns 'a' and 'b'.

Table B has 50 columns and 100G(or more) in size. It has the same 'a' and 'b' columns and same data in them.

If i'll use code like this

data SOMETHING;
set A(keep=a b);
something;

data SOMETHING;
set B(keep=a b);
something;

Would it be any difference in performance?
Or it doesn't matter which table I'll read - Big or Small. Message was edited by: Opa4ki
Super Contributor
Posts: 321

Re: Kepp dataset option. Reading large tables.

Hi,

You might want to test it yourself by adding the fullstimer option. Then try to compare the results.

Best Regards,
Milton
Respected Advisor
Posts: 3,908

Re: Kepp dataset option. Reading large tables.

I would expect that reading table A performes better as there should be less i/o.
As mentioned already fullstimer would give you some real values.

There was lately a interesting discussion in the SAS newsgroup which also might give you some insight:
http://groups.google.com.au/group/comp.soft-sys.sas/browse_thread/thread/7cc579c99df3badc?hl=en
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