function of DSNIDM and DSNIRNXT

Mike Bruzdzinski

function of DSNIDM and DSNIRNXT
We are experiencing a problem with a DB2-CICS transaction that had
sub-second response time a few moths ago and is now getting large number of
SQL calls and is spending a lot of time in the following DB2 Modules: DSNIDM
and DSNIRNXT.

We tried to locate some information about the modules. The best we could
find is some references to them in APARS.

Can anybody lend a hand and give a more complete explanation as to how these
modules are called and possibly why so frequently. The datasets are defined
as CLOSE NO

Thanks,

Michael Bruzdzinski
410-966-7185
SSA

Michael Bruzdzinski
410-966-7185

--- STANDARD DISCLAIMER --
ALTER TABLE EMAIL_POST
ADD EMPLOYER_RESPONSIBILITY CHAR(1);
UPDATE EMAIL_POST
SET EMPLOYER_RESPONSIBILITY = NULL;

(Translation for the SQL inept: My employer takes no
responsibility for my comments in this message.)



Dave Fox

Re: function of DSNIDM and DSNIRNXT
(in response to Mike Bruzdzinski)
Mike,

DSNIDM is the load module containing the Data Manager routines, of which
DSNIRNXT is one [see DSNSAMP(DSNWMODS) for brief routine description]. The
description for DSNIRNXT is "move CUB to next record", implying that a
cursor is moving from one record to the next in a sequential scan. See if
your accounting data shows an increased number of FETCH calls. Sounds to me
like an index may have been dropped, or you added a bunch of rows that
expanded the answer set of a previously small query.

[login to unmask email]
BMC Software, Inc.

-----Original Message-----
From: Bruzdzinski, Mike [mailto:[login to unmask email]
Sent: Tuesday, January 04, 2000 12:36 PM
To: [login to unmask email]
Subject: function of DSNIDM and DSNIRNXT


We are experiencing a problem with a DB2-CICS transaction that had
sub-second response time a few moths ago and is now getting large number of
SQL calls and is spending a lot of time in the following DB2 Modules: DSNIDM
and DSNIRNXT.

We tried to locate some information about the modules. The best we could
find is some references to them in APARS.

Can anybody lend a hand and give a more complete explanation as to how these
modules are called and possibly why so frequently. The datasets are defined
as CLOSE NO

Thanks,

Michael Bruzdzinski
410-966-7185
SSA

Michael Bruzdzinski
410-966-7185

--- STANDARD DISCLAIMER --
ALTER TABLE EMAIL_POST
ADD EMPLOYER_RESPONSIBILITY CHAR(1);
UPDATE EMAIL_POST
SET EMPLOYER_RESPONSIBILITY = NULL;

(Translation for the SQL inept: My employer takes no
responsibility for my comments in this message.)








Dan Courter (543-3870)

function of DSNIDM and DSNIRNXT
(in response to Dave Fox)
DSNIDM is the load module for DB2/390's data manager component.

DSNIRNXT is the "next record" csect in this load module. It is the
csect that moves forward to the next record to be accessed in a table
space scan. Performance of this module is affected by the degree of
clustering, segmentation, locking, selection expression etc., basically
anything that affects locating the next table record.

Dan