I have 2 files. One is an existing file that we have had on our system
for years and was created with DDS. The other one was just created
using SQL CREATE TABLE but has the same fields and lengths (I then
copied in all of the data from the existing file). There are 2 other
differences between these 2 files. The old one is a keyed physical
(not derivitave keys) and the old one has about 20 LF's over it.

When I run an interactive SQL over the SQL table version of this file,
it takes 10% of the time as running the same SQL over the DDS version.
I had thought that you needed to use an SQL table to utilize the SQE,
but as I read more, I no longer think that is the case.

So I went back and created another identical file, but this time with
DDS and with keys. It still takes far less time than running over the
older file. When I check, the SQL over the old file is using CQE and
the new file is using SQE. Why the difference? There are a few deleted
records in the old one, but a very small number.

I am trying to figure out how to utilize the SQE in all of our SQL
queries, but can't seem to find why some still use CQE. I am only
running interactive SQL statements, as I know Query/400 and QQRYAPI
will use CQE.

Can someone clear this up for me and tell me how to get all of my
existing files ot use SQE? Thanks very much in advance for any help.

Jeff Wilson

Jeff écrivait dans news:8949105a-45e5-452b-977e-
07ed1c3c0175 (AT) c26g2000vbq (DOT) googlegroups.com ce qui suit:

Did you check this web page ?

http://www-
01.ibm.com/support/docview.wss?uid=nas11aebc93ba6cab05c8625739c006b65 ee

(google search "sqe cqe engine site:ibm.com")

--
Cordialement
Marc Rauzier
(pour me répondre, ne pas utiliser le from mais le reply-to)

On Apr 6, 2:10*pm, Marc Rauzier <marc.vers.d... (AT) free (DOT) fr> wrote:
Marc

Thank you, I had. What I don't understand is that in the SQL Visual
Explain, it states that the reason it didn't use the SQE was "Derived
Key or sleect/omit index exists". But the PF does not have a derived
key and certainly doesn't haev select/omit. But maybe this means that
is there is ANY LF over this file that has a derived key or select/
omit then the file cannot use SQE? Is that right?

Thanks very much for your quick reply.

Jeff

Jeff écrivait dans news:0872e61e-6a9a-40f8-a07b-
95cf287c74ff (AT) v31g2000vbs (DOT) googlegroups.com ce qui suit:

I understand exactly as you wrote.

"The presence of a derived key or select/omit DDS defined logical files
over any of the physical tables being directly queried."

You could try to create also all the 20 logical files on your newly
created physical file and run your SQL again. Maybe the dispatcher will
use again CQE ?

--
Cordialement
Marc Rauzier
(pour me répondre, ne pas utiliser le from mais le reply-to)