Performance Questions and a little need for some education.

[Dan Lambshead]

Hi Ken,
 
  Just wondering what you mean by "Output Phase Read". Is that when you do
an Output ... if 1 = 2 ... or something like that, so you are only doing a
read? I have seen that before, but now am trying to remember what the
advantages are (if that's what you're talking about).
 
Dan

  _____  

From: powerh-l-bounces+dlambshe=milk.org at lists.sowder.com
[mailto:powerh-l-bounces+dlambshe=milk.org at lists.sowder.com] On Behalf Of
Ken Langendock
Sent: Tuesday, August 18, 2009 10:12 AM
To: powerh-l at lists.sowder.com
Subject: RE: Performance Questions and a little need for some education.



Unfortunately I have to agree with your client on the QTP/QUIZ argument. 

 

QTP is (IMHO) a much smarter tool to use for "simple, straight forward
extracts to create CSV files". QTP Allows you to do more with the extracts
than QUIZ. It also gives you more readable statistics to find problems than
QUIZ. QTP allows you to logically break up an extract into REQUESTS, where
QUIZ needs separate programs.

 

QUIZ also has/had a problem with extracting more than 32767 records into a
text file (NO HEAD, PAGE LENGTH 0), it inserted blank lines somewhere in the
middle of the file for no reason. After that I used QTP.

 

In short and IMHO, QUIZ is DUMB and should only be used to report the
contents of a subfile.

 

As for the TEMP/DEFINE issue, I agree with you.

 

I think the assumption that DEFINES are slower than TEMPS is a little
clouded. A straight DEFINE vs. a similar program than uses TEMPS is not
going to give you any major benefit.

If you have cascading DEFINES or DEFINES that are referenced multiple times,
then TEMPS would be a performance improvement as the DEFINE is re-evaluated
every time it is referenced and the TEMP is only evaluated once per record
complex.

 

BUT. If you incorporate OUTPUT PHASE READS and TEMPS, and/or TEMPS with an
AT statement.then you start leaving QUIZ and DEFINES far behind.

By OUTPUT PHASE READING all files that are NOT required in the record
complex (like Client Names, Address Types, etc), your record complex is much
smaller and therefore much faster.

 

Of course if you had the option of an SQL database, then you can move the
ACCESS statement into a CURSOR and retrieve only the columns you want,
everything increases exponentially.

 

Just my two cents worth. I've been doing this for a few years now and stick
to what I have proven works best. I did the same benchmarks back in the late
80's and found quiz was faster at dumping a file, but most programs never
stay that way. Sooner or later someone wants more in "that" report, so I
always start out calling my quiz-only programs ??R01B.QZS just in case I
need to add a QTP extract in front of it down the road.

 

Ken

 

From: powerh-l-bounces+ken.langendock=rogers.com at lists.sowder.com
[mailto:powerh-l-bounces+ken.langendock=rogers.com at lists.sowder.com] On
Behalf Of John Stires
Sent: August 18, 2009 9:46 AM
To: powerh-l at lists.sowder.com
Subject: [Bulk] Performance Questions and a little need for some education.

 

I have always been under the understanding that, in general, you use TEMP
ITEMs in QTP rather than DEFINEs.  The client where I am currently working
needs some convincing and is willing for me to run a bench test.   They use
QTP heavily for doing simple, straight forward extracts to create CSV files.
I have strongly suggested that QUIZ would be a much better tool or, at least
use TEMPs instead of DEFINEs.

 

I took one of their production extract QTP programs with loads of DEFINES
and converted them all to TEMP ITEMs.  This is the only difference.  The
original does not have as many cascading DEFINEs as most of their programs
so this is an even better test in comparing the performance of DEFINES vs.
TEMPs and then vs. QUIZ to create the same output file.

 

I ran my test programs numerous times manually on the development machine
and got execution times pretty much as I expected.

 

Records Processed          DEFINEs               TEMPs                  QUIZ

123,800                                 0:0:54                    0:00:53
0:00:45

 

Then I put them into a COM file and ran them with a SHOW TIME before and
after the programs.

 

Records Processed          DEFINEs               TEMPs                  QUIZ

123,800                                 0:0:53                    0:00:53
0:00:45

 

Then I took these three COM files to their production machine and got
totally unexpected results:

 

Records Processed          DEFINEs               TEMPs                  QUIZ

158,802                                 0:00:53                  0:01:01
0:00:57

 

The development machine is an ALPHA running OpenVMS V8.3 with PowerHouse
version 8.40.D running against RMS files..

The production machine is a Titanium running the same version of VMS and
PowerHouse.

 

Can someone explain to me how DEFINES can actually run faster the TEMPs and
even a comparable QUIZ program?  This kind of shakes my long standing belief
system in how QTP works.

 

Thanks,

John Stires

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.sowder.com/pipermail/powerh-l/attachments/20090818/c43cffaf/attachment.htm