RE: Evaluate complex conditions

["Richard Jackson" <richardjackson@xxxxxxxxxxxxxxxxxx>]

excellent suggestion.

The normal reasons for poor SQL performance are: (a) a query creates an
index, (b) a query creates a temporary file, (c) the query performs a large
sort, or (d) the query has to perform a table scan.  The messages in the job
log will tell you what it had to do.  Those messages may provide a hint for
what you can do to fix the problem.

Richard Jackson
mailto:richardjackson@richardjackson.net
http://www.richardjacksonltd.com
Voice: 1 (303) 808-8058
Fax:   1 (303) 663-4325

-|-----Original Message-----
-|From: owner-midrange-l@midrange.com
-|[mailto:owner-midrange-l@midrange.com]On Behalf Of Bill Erhardt
-|Sent: Thursday, October 26, 2000 3:17 PM
-|To: 'MIDRANGE-L@midrange.com'
-|Subject: RE: Evaluate complex conditions
-|
-|
-|If you experience performance problems using interactive SQL try
-|running it
-|in debug and then act on the suggestions.
-|
-|> -----Original Message-----
-|> From:       Richard Reeve [SMTP:richreeve@yahoo.com]
-|> Sent:       Thursday, October 26, 2000 4:11 PM
-|> To: MIDRANGE-L@midrange.com
-|> Subject:    Re: Evaluate complex conditions
-|>
-|> My experience is that both SQL and Query when run
-|> interactively are tremendous resource hogs.  Both
-|> should be run in batch or if interactive at a lower
-|> priority/timeslice than other interactive jobs.
-|>
-|> --- booth@martinvt.com wrote:
-|> > You suggest that an SQL process is not a performance
-|> > pig compared to
-|> > properly written RPGIV program.   Is there any
-|> > experience out there to
-|> > support or confute this?
-|> >
-|> > I ask because we notice that whenever one of the SQL
-|> > gurus starts an SQL
-|> > process off the command line all the rest of us
-|> > might as well go for
-|> > coffee until the SQL is done.
-|> >
-|> > _______________________
-|> > Booth Martin
-|> > Booth@MartinVT.com
-|> > http://www.MartinVT.com
-|> > _______________________
-|> >
-|> >
-|> >
-|> >
-|> > Marco Facchinetti <facchinetti@yahoo.com>
-|> > Sent by: owner-midrange-l@midrange.com
-|> > 10/25/2000 05:28 AM
-|> > Please respond to MIDRANGE-L
-|> >
-|> >
-|> >         To:     MIDRANGE-L@midrange.com
-|> >         cc:
-|> >         Subject:        Re: Evaluate complex
-|> > conditions
-|> >
-|> > Martin, if your purpose is a Query Tool my
-|> > experience says
-|> > that is better find something ready on the market.
-|> > About performance: if an sql statement is too heavy
-|> > the
-|> > same one done in (eg.) RPG will take a very long
-|> > time to be
-|> > executed. If you got the right logical files defined
-|> > in you
-|> > DB you'll get good performace if not....
-|> > Anyway if your are looking to eval or check an
-|> > expression
-|> > just remember tha procedure calls can be recursive,
-|> > so you
-|> > don't need any stack, procedures do it for you.
-|> >
-|> > Enjoy...
-|> >
-|> > --- booth@martinvt.com wrote:
-|> > > I have 4 problems with an SQL solution.
-|> > >
-|> > > 1-I don't know SQL well enough to  write the
-|> > strings on
-|> > > the fly.
-|> > > 2-Users I know can't fill in a command line string
-|> > > suitably for an SQL
-|> > > solution,
-|> > > 3-the few instances of SQL selections I've seen
-|> > have
-|> > > performance pigs in
-|> > > that SQL would suck in the sides of the machine in
-|> > an
-|> > > interactive job, and
-|> > > even with that still respond slowly.
-|> > > 4-giving users full flexibility with and/or
-|> > selections
-|> > > just doesn't work
-|> > > well.  Their intentions are good but the example
-|> > given
-|> > > yesterday is a
-|> > > wonderful example of the problem.  ( "give me all
-|> > > registered voters in New
-|> > > Hampshire and Vermont" will list just a few
-|> > energized
-|> > > citizens that like
-|> > > to vote early and vote often.)
-|> > >
-|> > > imho
-|> > > _______________________
-|> > > Booth Martin
-|> > > Booth@MartinVT.com
-|> > > http://www.MartinVT.com
-|> > > _______________________
-|> > >
-|> > >
-|> > >
-|> > >
-|> > > Marco Facchinetti <facchinetti@yahoo.com>
-|> > > Sent by: owner-midrange-l@midrange.com
-|> > > 10/24/2000 03:34 AM
-|> > > Please respond to MIDRANGE-L
-|> > >
-|> > >
-|> > >         To:     MIDRANGE-L@midrange.com
-|> > >         cc:
-|> > >         Subject:        Re: Evaluate complex
-|> > conditions
-|> > >
-|> > > SQL?
-|> > > --- booth@martinvt.com wrote:
-|> > > > Terry, the only method I've been able to create
-|> > and
-|> > > then
-|> > > > understand again
-|> > > > a week later, is to make a series of
-|> > subroutines.  Each
-|> > > > subroutine will
-|> > > > have a test for a condition and will flip a flag
-|> > if the
-|> > > > condition is not
-|> > > > met.  Something like this:
-|> > > >
-|> > > >  C    Eval      DoItFlag = 'Yes'
-|> > > >  C    Exsr    Test1
-|> > > >  C    If         DoItFlag = 'Yes' And Test1Flag
-|> > = 'Yes'
-|> > > >  C    EXSR   Test1SR
-|> > > >  C    End
-|> > > >  C    If         DoItFlag = 'Yes' And Test2Flag
-|> > ='Yes'
-|> > > >  C    EXSR   Test2SR
-|> > > >  C    End
-|> > > >  C    If         DoItFlag = 'Yes' And Test3Flag
-|> > = 'Yes'
-|> > > >  C    EXSR   Test3SR
-|> > > >  C    End
-|> > > >   C    If         DoItFlag = 'Yes'
-|> > > >  C    EXSR   OKToDoSR
-|> > > >  C    End
-|> > > >
-|> > > >
-|> > > > _______________________
-|> > > > Booth Martin
-|> > > > Booth@MartinVT.com
-|> > > > http://www.MartinVT.com
-|> > > > _______________________
-|> > > >
-|> > > >
-|> > > >
-|> > > >
-|> > > > Terry Grider <tgrider@arkansas.net>
-|> > > > Sent by: owner-midrange-l@midrange.com
-|> > > > 10/23/2000 12:43 PM
-|> > > > Please respond to MIDRANGE-L
-|> > > >
-|> > > >
-|> > > >         To:     MIDRANGE-L@midrange.com
-|> > > >         cc:
-|> > > >         Subject:        Re: Evaluate complex
-|> > conditions
-|> > > >
-|> > > > Sorry guys,  I didn't do a very good job of
-|> > explaining
-|> > > > what I was looking
-|> > > > for.
-|> > > > I don't mean I want code that is an example of
-|> > testing
-|> > > > for complex
-|> > > > conditions, I
-|> > > > mean I'm looking for code that will evaluate
-|> > statements
-|> > > > like the one in my
-|> > > > original example and determine the truth of the
-|> > > > statement.  You see, I'm
-|> > > > writing
-|> > > > a query tool and I want the user to be able to
-|> > provide
-|> > > > selection criteria
-|> > > > in an
-|> > > > english style IF format similar to cobol or
-|> > other query
-|> > > > tools I've seen. I
-|> > > > can
-|> > > > currently handle simple criteria with "and/or"
-|> > > > connectors, but I can't
-|> > > > seem to
-|> > > > come up with a good method for handling multiple
-|> > levels
-|> > > > of parenthesis.
-|> > > >
-|> > > > Terry Grider wrote:
-|> > > >
-|> > > > > Has anyone ever written or seen an example of
-|> > program
-|> > > > code designed to
-|> > > > > evaluate complex conditions?  For example, if
-|> > you
-|> > > > wanted to evaluate a =
-|> > > > > b and (c = d or c = e or c = f).  I'm looking
-|> > for
-|> > > > something that can do
-|> > > > > multiple levels of parenthesis and all
-|> > "and/or"
-|> > > > combinations.
-|> > > > >
-|> > > > > --
-|> > > > > Terry Grider
-|> > > > > tgrider@arkansas.net
-|> >
-|> >
-|> === message truncated ===
-|>
-|>
-|> =====
-|>
-|>
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