performance of db2 7 on mainframe

[luca.devoti]

hello,
I'm having a performance issue with a Windows CLI/ODBC application
that connects to a DB2 rel 7.1 on a mainframe of a bank.
I have to say I'm pretty new with this kind of environment.
The application is working, but it is much slower than when I run
against a DB2 7.1 on a poor Linux machine(using the same amount of
data in the tables used by the application).
I made some trace and I found the most noticeable difference is in the
time of the SQLExecute. Against the Linux is not relevant (the same
millisecond), against the mainframe it tooks an average of 2 cent of
sec.
This mainframe also has a long time in execution of SQLTables and
SQLColumns (almost 15 sec both), so that I've already fixed my
application to check for table existency and for information on the
columns, using a dummy select and SQLDescribeCol.
I'm now in dubt if:
-I have to reengineer the logic of the application or
-the fact it run faster on a poor Linux machine meas that there are
underlining problem with something outside of my app

thanks in advance to anyone who can answer
LD

[Norm]

On Nov 19, 3:50 pm, [e-mail] wrote:

hello,
I'm having a performance issue with a Windows CLI/ODBC application
that connects to a DB2 rel 7.1 on a mainframe of a bank.
I have to say I'm pretty new with this kind of environment.
The application is working, but it is much slower than when I run
against a DB2 7.1 on a poor Linux machine(using the same amount of
data in the tables used by the application).
I made some trace and I found the most noticeable difference is in the
time of the SQLExecute. Against the Linux is not relevant (the same
millisecond), against the mainframe it tooks an average of 2 cent of
sec.
This mainframe also has a long time in execution of SQLTables and
SQLColumns (almost 15 sec both), so that I've already fixed my
application to check for table existency and for information on the
columns, using a dummy select and SQLDescribeCol.
I'm now in dubt if:
-I have to reengineer the logic of the application or
-the fact it run faster on a poor Linux machine meas that there are
underlining problem with something outside of my app

thanks in advance to anyone who can answer
LD

Do you have dynamic statement caching turned on the DB2 for z/OS? A
detailed performance trace on the mainframe side will indicate where
the time is being spent.

Norm

[Norm]

On Nov 19, 3:50 pm, [e-mail] wrote:

hello,
I'm having a performance issue with a Windows CLI/ODBC application
that connects to a DB2 rel 7.1 on a mainframe of a bank.
I have to say I'm pretty new with this kind of environment.
The application is working, but it is much slower than when I run
against a DB2 7.1 on a poor Linux machine(using the same amount of
data in the tables used by the application).
I made some trace and I found the most noticeable difference is in the
time of the SQLExecute. Against the Linux is not relevant (the same
millisecond), against the mainframe it tooks an average of 2 cent of
sec.
This mainframe also has a long time in execution of SQLTables and
SQLColumns (almost 15 sec both), so that I've already fixed my
application to check for table existency and for information on the
columns, using a dummy select and SQLDescribeCol.
I'm now in dubt if:
-I have to reengineer the logic of the application or
-the fact it run faster on a poor Linux machine meas that there are
underlining problem with something outside of my app

thanks in advance to anyone who can answer
LD

Your SQLTables and SQLColumns queries running long is typical in an
out-of-the-box usage. Many DB2 for z/OS single sub-systems have
thousands of tables and tens of thousands of columns. There are
parameters in the db2cli.ini that can be used to limit the amount of
schema information you download.

Missing statistics, bufferpool selection, no dynamic statement
caching, network latency, CPU busy, system paging etc. can lead to
poor performance outside of your application. Your local DBA should
be able to trace the problem. There's no reason you shouldn't get the
same or better performance on the DB2 for z/OS system.

Norm