AW: Interupting an rpg sql search

Hi,

Creating the file (or maybe it's a field option, I don't recall) with
sort sequence *LANGIDSHR and compiling the program(s) with the same option

will allow the system to do case insensitive searches
which will allow you to get rid of the UPPER() functional.
If you sort the results, it will also order them in a more natural way
(boo and Baa will show as Baa, boo instead of boo, Baa).

Also, make sure you have an index over your file over any fields
that you are doing an equals comparison with and any fields in your order

by clause.

But you need access paths (either keyed logical files or SQL index) built
with sort sequence *LANDIDSHR. Access path with other sort sequences are not
considered.

Also, make sure that any existing logical files you think it should use
do not have select/omit criteria in them. The query optimizer will not

consider those.

Only the SQE query optimizer can not consider logical files with select/omit
clauses.
If there are logical files with select/omit clauses built over the physical
files, all queries are rerouted to the CQE as long as not
IGNORE_DERIVED_INDEX = *YES is not specified in the QAQQINI file used for
this job. If IGNORE_DERIVED_INDEX *YES is specified queries that access
physical files with logical files with select/omit clauses can be executed
by the SQL, but all access paths stored in keyed logical files with
select/omit clauses will be ignored.

Mit freundlichen Grüßen / Best regards

Birgitta Hauser

"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)
"If you think education is expensive, try ignorance." (Derek Bok)
"What is worse than training your staff and losing them? Not training them
and keeping them!"

-----Ursprüngliche Nachricht-----
Von: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] Im
Auftrag von Haas, Matt (CL Tech Sv)
Gesendet: Friday, January 18, 2008 20:21
An: RPG programming on the AS400 / iSeries
Betreff: RE: Interupting an rpg sql search


Creating the file (or maybe it's a field option, I don't recall) with sort
sequence *LANGIDSHR and compiling the program(s) with the same option will
allow the system to do case insensitive searches which will allow you to get
rid of the UPPER() functional. If you sort the results, it will also order
them in a more natural way (boo and Baa will show as Baa, boo instead of
boo, Baa).

Also, make sure you have an index over your file over any fields that you
are doing an equals comparison with and any fields in your order by clause.
Order of the fields in the index makes a difference. You want the fields in
your where clause first and then the fields in your order by clause. Also,
make sure that any existing logical files you think it should use do not
have select/omit criteria in them. The query optimizer will not consider
those. Finally, if you have an index you think it should be using and it
doesn't, try ordering the results by the first field in the index.

Matt

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of Wilt, Charles
Sent: Friday, January 18, 2008 9:54 AM
To: RPG programming on the AS400 / iSeries
Subject: RE: Interupting an rpg sql search

So the problem isn't that you can't interrupt it, the problem is that it is
taking too long.

I see two problems with your SQL.

Using the UPPER() function on a column.
Using '%ZONE%'

-- both of which force a full table scan.

I don't know off the top of my head if it will help, but first try
reordering the where clause like
so:

Dynstm = select * from clientfile where city = 'NY'
And upper(name) like '%ZONE%'
fetch first 25 rows only

Otherwise try:

With table as ( select * from clientfile
Where city = 'NY'
)
Select * from tbl
Where upper(name) like '%ZONE%'


Might be helpful depending on how many of the 1/2 million records have city
= 'NY'.

If none of the above helps (enough), then the only option is to build a
separate dictionary file. Still, depending on the results you're looking for
with the LIKE, things could get tricky.

For instance, '%ZONE%' would find:
'AUTOZONE'
'END ZONE TAVERN'

The first one is the problem, the second can be found by having a dictionary
file built like so
Key token
1234 END
1234 ZONE
1234 TAVERN

Then having an index over the dictionary that can be used by using: 'ZONE%'
Additionally, consider the SOUNDEX function:
http://www.systeminetwork.com/artarchive/index.cfm?fuseaction=viewNewsletter
Article&articleID=54444&we
bID=1001

or http://tinyurl.com/29rsqn

HTH,

Charles Wilt
Software Engineer
CINTAS Corporation - IT 92B
513.701.1307
wiltc@xxxxxxxxxx

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of tim
Sent: Friday, January 18, 2008 9:27 AM
To: 'RPG programming on the AS400 / iSeries'
Subject: RE: Interupting an rpg sql search

Here is the code I am refering to. The user may want to search for
%beauty% in the name field of the client file. The client file has
about 1/2 million
records. So this may take a while. This also needs to be done interactive
since they want what they want when they want it :)

Dynstm is built by user requirements. So it can be more complicated.

Dynstm = select * from clientfile where upper(name) like '%ZONE%'
and city = 'NY' fetch first 25 rows only

exec sql set option datfmt=*usa;
exec sql prepare s2 from :dynstm;
exec sql declare c2 cursor for s2;
exec sql open c2;
exec sql fetch c2 into :thefileds;
dow sqlcod = 0;
blah blah blah
enddo

The user will hit enter and can wait as long as a minute. So, in turn,
they close out the client access window which really makes a mess.




-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of rob@xxxxxxxxx
Sent: Friday, January 18, 2008 8:57 AM
To: RPG programming on the AS400 / iSeries
Subject: Re: Interupting an rpg sql search

I take it you're talking about the RPG we all know and love and not
some client/server version like VARPG? I don't think you'll find a
whole lot on "event programming" with RPG or RPGLE. That's what might
interrupt a long running process. You're pretty much restricted to
ENDJOB or SysReq. (Typically mapped to Shift-Esc on a PC keyboard).
Normally you'd use option 2. However, on some long runners like that,
I've had to use option 90 to force a sign off because option 2 would
tell me something like it couldn't be halted during the middle of some
critical operation or some such thing.

I'd really evaluate that SQL statement. Traditional wisdom is to do a
STRDBG UPDPROD(*YES) and do not specify a program name. After the
program is done you can do a DSPJOBLOG and you'll see tons of SQL
stuff in there to look at.

Another consideration is CHGQRYA QRYTIMLMT(15)

After doing a little poking around, you might post the SQL statement
and we can see if you really flubbed it up. Hey, even I've made
mistakes. :-)

I don't suppose there's some way to throw a halt indicator? (Ducking
and
running.)

Rob Berendt
--
Group Dekko Services, LLC
Dept 01.073
PO Box 2000
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com





"tim" <tim2006@xxxxxxxxxxx>
Sent by: rpg400-l-bounces@xxxxxxxxxxxx
01/18/2008 08:43 AM
Please respond to
RPG programming on the AS400 / iSeries <rpg400-l@xxxxxxxxxxxx>


To
"'RPG programming on the AS400 / iSeries'" <rpg400-l@xxxxxxxxxxxx> cc

Subject
Interupting an rpg sql search






I have a SQLRPGLE program that does a search using "like" over a large
file. The search can take a bit a time in some cases. I would like to
be able to stop the search by hitting a key (say esc key tied to an
attention program).



Can this be done? Or are there other techniques I can use. I've tried
the "fetch first 25 rows only" clause, but the search still can take a
long time.





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