Self-defining sections

Use this topic as a reference for format of the self-defining sections of the SMF record.

A self-defining section of a type 115 SMF record tells you where to find a statistics record, how long it is, and how many times that type of record is repeated (with different values). The self-defining sections follow the header, at fixed offsets from the start of the SMF record. Each statistics record can be identified by an eye-catcher string.

The following types of self-defining section are available to users for type 115 records. Each self-defining section points to statistics data related to one of the IBM® MQ components. Table 1 summarizes the sources of the statistics, the eye-catcher strings, and the offsets of the self-defining sections from the start of the SMF record header.

Table 1. Offsets to self-defining sections
Source of statistics	Record subtype (SM115STF)	Offset of self-defining section		Eye-catcher of data
Source of statistics	Record subtype (SM115STF)	Dec	Hex	Eye-catcher of data
Storage manager	1	100	X'64'	QSST
Log manager	1	116	X'74'	QJST
Message manager	2	36	X'24'	QMST
Data manager	2	44	X'2C'	QIST
No longer used. The self-defining section will be binary zeros.	2	52	X'34'
Lock manager	2	60	X'3C'	QLST
Db2® manager	2	68	X'44'	Q5ST
Coupling Facility manager	2	76	X'4C'	QEST
Topic manager	2	84	X'54'	QTST
SMDS usage	2	92	X'5C'	QESD
Buffer manager - one for each buffer pool	215	36	X'24'	QPST
Channel initiator	231			QWSX
Data manager page set - one for each page set	201	36	X'24'	QIS1
Storage manager	5	36	X'24'	QSPH
Storage manager	6	36	X'24'	QSGM
Storage manager	7	36	X'24'	QSRS
Queues	216	36	X'24'	QQST

Note: Some of the storage manager information in subtype 5, 6 and 7 records is intended only for IBM use. Other self-defining sections that are not listed contain data for IBM use only.

Each self-defining section is two fullwords long and has this format:

ssssssssllllnnnn

where:

ssssssss is a fullword containing the offset from the start of the SMF record.
llll is a halfword giving the length of this data record.
nnnn is a halfword giving the number of data records in this SMF record.

For more information see, Examples of SMF statistics records.

Note: Always use offsets in the self-defining sections to locate the statistics records.

QWHX header

The QWHX header contains the queue manager release in the form VVRRMM, and the name of the queue sharing group that the queue manager is a member of. The QWHX is described in assembler macro thlqual.SCSQMACS(CSQDQWHX).

The QWHX header is available in all SMF 115 subtypes and can be located from the self defining section, which is at offset 28 (X'1C') from the beginning of each record, as follows:

Take the fullword offset, ssssssss, from the self defining section and add 52 bytes (X'34') to it, this offset is the start of the QWHX header.