-MODIFY TRACE command (Db2)

The -MODIFY TRACE command changes the IFCIDs (trace events) associated with a particular active trace.

The -MODIFY TRACE command completes the following actions:
  • Changes the trace events (IFCIDs) being traced for a particular active trace.
  • Stops any IFCID previously active for the specified trace.
  • Writes statistics records.

Abbreviation: -MOD TRA

Environment for -MODIFY TRACE

This command can be issued from a z/OS® console, a DSN session, a DB2I panel (DB2 COMMANDS), an IMS or CICS® terminal, or a program using the instrumentation facility interface (IFI).

Data sharing scope: Member

Traces started by a IFI/IFC program: Before you modify an active trace, ensure that an IFI application program or the IFC Selective Dump utility (DSN1SDMP) did not start the trace. If you modify a trace started by DSN1SDMP, the DSN1SDMP utility abnormally terminates. When DSN1SDMP terminates, it stops the trace. This stop could interfere with the MODIFY TRACE command, which stops and restarts the trace.

Authorization for -MODIFY TRACE

To execute this command, you must use a privilege set of the process that includes one of the following privileges or authorities:
  • TRACE privilege
  • SQLADM authority
  • System DBADM authority
  • SYSOPR authority
  • SYSCTRL authority
  • SYSADM authority
  • SECADM authority

Db2 commands that are issued from a logged-on z/OS console or TSO SDSF can be checked by Db2 authorization using primary and secondary authorization IDs. Start of changeA logged-on z/OS user ID must be defined in RACF or a similar security server.End of change

Syntax for -MODIFY TRACE

Read syntax diagramSkip visual syntax diagramMODIFY TRACE(PERFMACCTGSTATAUDITMONITOR)CLASS(*,integer)TNO( integer)IFCID(*,ifcid_nbr)COMMENT( string)

Option descriptions for -MODIFY TRACE

TRACE
Determines which IFCIDs are started. The following table lists each trace type, its abbreviation, and a brief description of each type.

One additional trace type is not described in the table because it is intended for service and is to be used under the direction of IBM® Support.

Table 1. Trace types
Type Abbreviation Description
PERFM P Performance records of specific events
ACCTG A Accounting records for each transaction
STAT S Statistical data
AUDIT AU Audit data
MONITOR MON Monitor data
CLASS( integer , …)
Limits the list to IFCIDs started for specified classes.

Abbreviation: C

integer is a class to which the list of IFCIDs started is limited.

The default is CLASS( * ) , which starts all default IFCID classes.

TNO( integer )
FL 506 Specifies the particular trace to be modified, identified by its trace number (1 to 64, 01 to 09). You can specify only one trace number. TNO is a required option for the MODIFY TRACE command.

No default exists for the TNO keyword.

IFCID( ifcid_nbr , …)
Specifies which other IFCIDs (trace events), in addition to those IFCIDs contained in the classes specified in the CLASS option, are to be started. To start only those IFCIDs specified in the IFCID option, use trace classes 30-32. These classes have no predefined IFCIDs and are available for a location to use.

If you do not specify the IFCID option, only those IFCIDs contained in the activated trace classes are started.

The maximum number of IFCIDs is 156. The range of values that are valid for the IFCID option is 1 through 350, with the exception of: 4, 5, 185, 187, 217, 232, 234, 240, and 241.

The default is IFCID( * ).

COMMENT ( string )
Specifies a comment that is reproduced in the trace output record (except in the resident trace tables).

string is any character string; it must be enclosed between apostrophes if it includes a blank, comma, or special character.

Example for -MODIFY TRACE

Example 1:Change trace number six so that it collects only statistics and accounting data. You can define CLASS(30) at your site. 
-MODIFY TRACE(S) IFCID(1,2,3) TNO(6) CLASS(30)
  COMMENT ('STATS AND ACCOUNTING ON')