Re: Logical file and query question

I read something many releases of OS/400 ago that, if a query is using a
logical file and is likely to select a large percentage (can't remember the
exact figure) of the file contents, then the system tends to disregard the
logical file access path.


regards


James O'Sullivan
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             "Greg Wenzloff"                                               
             <GWenzloff@beckmf                                             
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                                       Logical file and query question     
             16/08/2005 14:14                                              
                                                                           
                                                                           
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I created a logical file over a rather large physical file to help speed
up a long running program.  I'd like to look at the data retrieved by
the logical file so I can get ready to test the changed program.

When I do RUNQRY *N FILENAME the system returns "Query running. Creating
a copy of file FILENAME in LIBNAME".   This grinds away for a long long
time and I have to kill my session.

>From Google I find that this message comes from OPNQRYF.

The question is what's going on here?   If there is an access path
created by the CRTLF command why doesn't it just display the data?
Other logical files instantly display records.

The DDS for the LF does contain select and omit directives.   Is that
any significance?   I don't think the program will run quicker if the
operating system is going to build its own path to the data.

Here is the DDS
...A..........T.Name++++++.Len++TDpB......Functions+++++++++++++++
   A          R IMHISTR                   PFILE(IMHIST)
   A*
   A            CONO
   A            TCODE
   A            ITNBR
   A            HOUSE
   A            TRNDT
   A            TRQTY
   A*
   A          K ITNBR
   A          K TRNDT
   A*
   A          S TCODE                     COMP(EQ 'SA')
   A          S TCODE                     COMP(EQ 'IS')
   A          O CONO                      COMP(EQ 9)
   A          O TRQTY                     COMP(EQ 0)
   A          O                           ALL

TIA,
Greg



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