SEO

#1 (**permalink**) 02-27-2008, 12:10 PM

Hello, When I use db2exfmt to generate the explain plan, under the
Operator section I can see the following arguments listed
[1] EARLYOUT
[2] FETCHMAX
[3] ISCANMAX
but I'm not sure what it means. Can someone share their experience
with these operators ?

#2 (**permalink**) 02-27-2008, 12:10 PM

Sam Durai wrote:
> Hello, When I use db2exfmt to generate the explain plan, under the
> Operator section I can see the following arguments listed
> [1] EARLYOUT
Specifies that the operation doesn't have to be completed.
The most common example is EXISTS processing. No need to collect all the
rows in teh query. It's sufficient to find any.
> [2] FETCHMAX
> [3] ISCANMAX
Both related to prefetching. It limits how many rows are prefetched.
Usages include OPTIMIZE FOR n ROWS or FETCH FIRST n ROWS

Cheers
Serge

--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

SEO

db2exfmt - Earlyout, Fetchmax, Iscan Operator