Re: Sorting

[Douglas Handy <dhandy1@xxxxxxxxxxxxx>]

Pat,

>I have seen any number of tests that show FMTDTA as faster than any
>other method of "sorting"... OPNQRYF will get much closer with
>logicals but since you don't know the final sequence, that's 
>gonna be a tougher nut to crack.

My understanding has been that since the addition of ALWCPYDTA(*OPTIMIZE) as an
option to OPNQRYF, that under the covers OPNQRYF will use the exact same sort
engine as FMTDTA when the optimizer determines a sort will be the most efficient
method under the circumstances.  This tends to be the case when you are
selecting all or most of the records in the file.

ALWCPYDTA(*OPTIMIZE) was added back at V2Rx, as I recall.  I prefer it over
FMTDTA because it lets me specify field names rather than record offsets.

See the parameter's help text under OPNQRYF, as it gives more information, and
the restrictions on when *OPTIMIZE is allowed.

Doug