/TRACE LINK command

Subsections:

• Environment
• Syntax
• Keywords
• Examples

Environment

The following table lists the environments (DB/DC, DBCTL, and DCCTL) in which you can use the commands and keywords.

Syntax

A

Keywords

The following keywords are valid for the /TRACE LINK command:

LEVEL

Expands the LINE, LINK, NODE, or UNITYPE trace functions. The LEVEL specification is for the entire IMS system and is changed only by reissuing /TRACE with different values or by restarting the IMS control region.

LEVEL indicates the extent of the control block trace information desired. The indicated control blocks are only traced at relevant times. All levels are inclusive of numerically lower levels. The following list displays the levels and their associated blocks.

Level

Blocks

1

CLB (DECB) or LLB(MSC)

CTB or LTB(MSC)

IOB (for non-VTAM lines) or IOSB (MSC for channel-to-channel links)

2

CNT or LNB(MSC)

CXB

CRB

CIB

CCB

PD stack

3

queue manager buffers

Input/output line buffers

LXB (for channel-to-channel links and processor storage to processor storage)

4

save area sets (IMS dispatching)

If the first /TRACE SET ON command does not specify LEVEL, a default of 4 will be used. Specifying LEVEL on subsequent commands will change the defaults.

MODULE

Is used to expand the LINE, LINK, NODE, or UNITYPE trace functions. The MODULE specification is for the entire IMS system and is changed only by reissuing /TRACE with different values or by restarting the IMS control region.

MODULE indicates which modules are to have their control blocks traced.

ALL

Both device-dependent module (DDM) and MFS

DDM

Communication analyzer and device-dependent module interfaces

MFS

Communication analyzer and Message Format Service module interfaces

If the first /TRACE SET ON command does not specify MODULE, a default of ALL will be used. Specifying MODULE on subsequent commands will change the defaults.

TAKEOVER

Controls tracing during takeover only, and is separate from regular tracing. TAKEOVER tracing can be set for LINE, LINK, NODE, and UNITYPE keywords.

TAKEOVER only applies in an XRF environment. When TAKEOVER is used with SET OFF, the trace is turned off before takeover. When an output message is dequeued for a terminal, takeover tracing will stop for that terminal.

If both regular and takeover tracing are entered, the most recent setting will override any previous settings; for example, takeover tracing will override regular tracing if regular tracing was entered first. This means that either regular or TAKEOVER tracing can be in effect, but not both.

/TRACE TAKEOVER can be issued only from an XRF active system. It is rejected if entered from an alternate or non-XRF system. It is recovered across restart and takeover, and only needs to be entered once until cold start. Tracing occurs only if the session was active at the time of the takeover.