Output from DB2 for Z/OS version 7 precompiler VS version 5.

Peter Zillo Jensen

Output from DB2 for Z/OS version 7 precompiler VS version 5.
Hello,

Do anyone have experience with the code generated by the V7 precompiler
versus V5 precompiler.
We have a customer that sees an increase of generated code lines by 240%.
Making the resulting load module approx 25% larger.
Is there some options that we have overseen?

Regards, Peter Zillo



Chris Bowen

Re: Output from DB2 for Z/OS version 7 precompiler VS version 5.
(in response to Peter Zillo Jensen)
Peter,

We found that the way the DB2 precompiler handles COBOL host variables are
changed between V5 & V6.

From V6 all host variables are passed backwards and forwards via an SQLDA
block which the precompiler builds into working-storage. This has
implications for program sizes both because of the effect on working-storage
and because of the extra moves needed to populate the SQLDA for each SQL
statement involving host variables. Programs with a lot of SQL and
program-logic code or that use very large numbers of host variables would be
likely to grow significantly.

I haven't been able to find any documentation that is specific about this
change but I guess that the V6 requirement for all host variables to be
prefixed with ':' had the same driver.

HTTH.

Chris Bowen
Macro 4 plc



-----Original Message-----
From: Peter Zillo Jensen [mailto:[login to unmask email]
Sent: 15 January 2003 12:37
To: [login to unmask email]
Subject: Output from DB2 for Z/OS version 7 precompiler VS version 5.


Hello,

Do anyone have experience with the code generated by the V7 precompiler
versus V5 precompiler.
We have a customer that sees an increase of generated code lines by 240%.
Making the resulting load module approx 25% larger.
Is there some options that we have overseen?

Regards, Peter Zillo








Roger Miller

Re: Output from DB2 for Z/OS version 7 precompiler VS version 5.
(in response to Chris Bowen)
Here is a paste from the V7 Installation Guide section on migration from V5
to V7 on incompatibilities.

Support for large objects: The following incompatibilities result from the
expansion of the SQLDA to support large objects:
o Because of the additional data types supported after Version 5, the host
language statements generated by the precompiler for each SQL statement
include a larger parameter list. As a result, the size of the object code
that results from compiling the output of the precompiler increases. This
increase varies according to the number of host variables that are
specified in an SQL statement.
o INCLUDE SQLDA generates additional fields for applications written in
assembler, PL/I, C, and C++ (see Appendix C of DB2 SQL Reference for
descriptions of these fields). If an SQL application program written in one
of those languages defines a name that matches any symbol in the additional
fields, and the program also uses INCLUDE SQLDA, then that program might not
operate, assemble, or compile correctly.

Basically, the structures we have been using for 20 years can't hold all of
the bits we need, and the SQLDA did not change for about ten releases, so
the big increase came in V6.

Roger Miller

On Wed, 15 Jan 2003 13:57:46 -0000, Chris Bowen <[login to unmask email]>
wrote:

>Peter,
>
>We found that the way the DB2 precompiler handles COBOL host variables are
>changed between V5 & V6.
>
>From V6 all host variables are passed backwards and forwards via an SQLDA
>block which the precompiler builds into working-storage. This has
>implications for program sizes both because of the effect on working-
storage
>and because of the extra moves needed to populate the SQLDA for each SQL
>statement involving host variables. Programs with a lot of SQL and
>program-logic code or that use very large numbers of host variables would
be
>likely to grow significantly.
>
>I haven't been able to find any documentation that is specific about this
>change but I guess that the V6 requirement for all host variables to be
>prefixed with ':' had the same driver.
>
>HTTH.
>
>Chris Bowen
>Macro 4 plc
>
>
>
>-----Original Message-----
>From: Peter Zillo Jensen [mailto:[login to unmask email]
>Sent: 15 January 2003 12:37
>To: [login to unmask email]
>Subject: Output from DB2 for Z/OS version 7 precompiler VS version 5.
>
>
>Hello,
>
>Do anyone have experience with the code generated by the V7 precompiler
>versus V5 precompiler.
>We have a customer that sees an increase of generated code lines by 240%.
>Making the resulting load module approx 25% larger.
>Is there some options that we have overseen?
>
>Regards, Peter Zillo
>
>
>
the
>
>
>
>
>
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