Re: LF on 2 files with 'UNION'

[rob@xxxxxxxxx]

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Thanks for the research.

Rob Berendt
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"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
Benjamin Franklin




Vern Hamberg <vhamberg@centerfieldtechnology.com>
Sent by: midrange-l-admin@midrange.com
11/06/2002 06:38 PM
Please respond to midrange-l

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        Subject:        Re: LF on 2 files with 'UNION'


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Rob

Lest this become another limitation vs. feature discussion, I'll plow on
ahead  ;-)

A view cannot be read in RPG because it does not have an access path in it
- only an SQL statement that has to be executed whenever you access it.
Native IO cannot execute an SQL statement, it uses an ODP that is based on
an access path, which is maintained in realtime.

Here's an example, based on a TPC-H benchmark file called LINEITEM. I
create both a view that selects all fields in records with order number >
2,500,000.

The view:
CREATE VIEW TPCH/L_VW AS SELECT * FROM tpch/lineitem WHERE
l_orderkey > 2500000

Size is 32,768 bytes
It is usable right away
Block size c.91,000 records (the increment you see at the bottom
interactive SQL)
19 seconds to see first record in interactive SQL

The S/O logical:
      A          R LINEITEM                  PFILE(TPCH/LINEITEM)
      A          K *NONE
      A          S L_ORDERKEY                COMP(GT 2500000)
      A          O                           ALL

Size is 56,725,504 bytes
It took a long time to build
Block size 20,000 records
53 seconds to see first record in interactive SQL -- VERRRY interesting!

Haven't tried the logical in RPG - I assume it'd get the first selected
faster, but I'm not sure.

Regards

Vern

At 04:00 PM 11/6/2002 -0500, you wrote:
>Hope the new view is working for you.  I still can't get to open as a lf
>with traditional RPG.
>
>Either you can do more research on RNX1011.  Or realize the limitations
of
>traditional RPG and accept SQL.
>
>Rob Berendt
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