Re: SQL Date Math

That was interesting. Here are the results.

All run in interactive SQL, approximately 56M records. Index built
over the numeric field (which took a freaking long time btw - like 10
minutes).

Using CvtDateToNumISO function with no index - 45 seconds
Using function code with no index - 38 seconds
Using CvtDateToNumISO function with index - 11 seconds
Using function code with index - 2 seconds

On Nov 13, 2007 7:05 PM, Michael Ryan <michaelrtr@xxxxxxxxx> wrote:

Yes...going from date to numeric. I just named it backwards to throw
off the opposition. :)

Sure...I'll give it a go first thing in the morning, and I'll post my
results back here. I'll also create an index over the numeric field
and see how that helps things.

On Nov 13, 2007 5:28 PM, Elvis Budimlic

<ebudimlic@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

Michael,

Do you mean CvtDateToNumISO? Going from DATE to NUMERIC, not the other way
around.

If so, do you mind running another test?

Take Charles' code out of the UDF and put it in the SQL statement itself.
Then run it.
I'm curious to see if UDF call itself contributes any significant overhead.

BTW, do you have an index over the numeric(8,0) field?
If not, I think it would be worth running a test again after you create one.

Elvis

Celebrating 10-Years of SQL Performance Excellence on IBM i5/OS and OS/400
http://centerfieldtechnology.com/training.asp


-----Original Message-----
Subject: Re: SQL Date Math

Charles' CvtNumtoDateISO function works swell! It takes 120 seconds
for my query (56M records) using the date and substr method, and 39
seconds for the CvtNumToDateISO method. And that's on the development
system. Much faster on the production system.




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