GTF trace report

The GTF trace report shows timestamps and the number of records for each GTF trace data set that is included in the report job.

The following example shows a GTF trace report that includes two input GTF trace data sets. For each trace data set, the start and end times of the trace data and the elapsed time of each trace are shown. The number of records of each type are also shown, including breakdowns for OSAM, VSAM, and DEDB record, by type, of GTF trace record.

In addition, the GTF trace report provides information on lost records and lost blocks. Lost records occur when GTF buffers fill, and no buffer space is available for additional trace records. Lost blocks typically occur during write errors to the trace data set or during periods of very high trace activity. After trace buffers become available, GTF writes an error record that provides information on the number of trace records that were discarded for lack of buffer space. The report shows both the number of GTF error records and the total number of trace records that were discarded.

Figure 1. GTF trace report


PAGE      1   IMS BUFFER POOL ANALYZER 1.4.0     DATE: 08/30/2021
GTF TRACE REPORT              IMS IMB1           TIME: 19:35:30
  
GTF TRACE DATA FOR INPUT DATASET DDNAME=TRACE  DSN=P390M.BPL.TRACE.SVL3

                 NUMBER                                      ELAPSED 
 GTF RECORD TYPE RECORDS  START TIME        END TIME          SECONDS  
 --------------- -------- ---------------   ----------------- --------- 
 CONTROL           6,001  2021.074 20:03:12 2021.074 20:04:43    91.0 
 BFR POOL ANAL     1,909  2021.074 20:03:14 2021.074 20:03:14     0.0
 OSAM            1909.5K  2021.074 20:03:12 2021.074 20:04:43    91.0
    BLOCK LOCATE  363.4K
    BYTE  LOCATE 1541.2K
    CREATE BLOCK  4,810

VSAM              329.8K  2021.074 20:03:12  2021.074 20:04:43   91.0
    GET           329.8K 
UNKNOWN TYPE           0 
LOST RECORDS           0 
LOST BLOCKS            0
TOTAL            2247.2K
  
GTF TRACE DATA FOR INPUT DATASET DDNAME=TRACE2 DSN=P390M.BPL.TRACE 
   
                 NUMBER                                       ELAPSED 
GTF RECORD TYPE RECORDS  START TIME        END TIME          SECONDS  
--------------- -------- ---------------   ----------------- ---------
CONTROL           2      2021.198 16:42:14 2021.198 16:45:41   206.4 
BFR POOL ANAL   141      2021.198 16:42:16 2021.198 16:45:41   205.2 
OSAM              0  
VSAM              0
UNKNOWN TYPE      0 
LOST RECORDS      0 
LOST BLOCKS       0
TOTAL           145

The reference information that is provided in the GTF trace report includes the following fields:

CONTROL

A GTF record type that shows the number of control records that were produced by GTF that are not used by IMS Buffer Pool Analyzer.

BFR POOL ANAL

These are records are generated by IMS Buffer Pool Analyzer. Records might include information on subpool definitions, DBDS information, control records, or DEDB lookaside buffer statistics.

OSAM

Shows information about the OSAM trace records that are produced by IMS. OSAM GTF trace record subtypes are also listed as appropriate. The OSAM subtype can be an OSAM request type, DIFFERNT IMS, or UNKNOWN.

OSAM request type

Indicates the number of records for each OSAM request type. The hexadecimal OSAM-related buffer handler function code that is set in the record is converted to a meaningful text string for this report. See the following table for possible values:

Hexadecimal value	Subtype
E1	BLOCK LOCATE
E2	BYTE LOCATE
EB	BYTLOC+MARK (This subtype represents "Byte locate and mark the buffer as altered")
E4	CREATE BLOCK

DIFFERNT IMS

The number of OSAM records from other subsystems.

UNKNOWN

The number of records other than those listed under one of OSAM request types or DIFFERNT IMS.

VSAM

Shows information about the VSAM trace records that are produced by VSAM. VSAM GTF trace record subtypes are also listed as appropriate. The VSAM subtype can be a VSAM request type, NOT IMS DB, or UNKNOWN.

VSAM request type

Indicates the number of records for each VSAM request type. The hexadecimal RPLREQ (RPL request type) value that is set in the record is converted to a meaningful text string for this report. See the following table for possible values:

Hexadecimal value	Subtype
00	GET
01	PUT
02	CHECK
03	POINT
04	ENDREQ
05	ERASE
06	VERIFY
07	IMPORT/JESFM ("JESFM" stands for "JES FORMAT")
08	DATA PREFMT ("PREFMT" stands for "PREFORMAT")
09	INDEX PREFMT ("PREFMT" stands for "PREFORMAT")
0A	FORCE I/O
0B	RPLREQ=0B
0C	RPLREQ=0C
0D	RPLREQ=0D
0E	RPLREQ=0E
0F	RPLREQ=0F
10	CNVTAD
11	MNTACQ
12	ACQRANGE
13	TERMRPL
14	VERIFY REFR ("REFR" stands for "REFRESH")
15	LKADD
16	LKREQ
17	LKCD
18	INQRC
19	RETLK
1A	RECOV REQ
1B	QUIESE REQ
1C	EADD REQ

NOT IMS DB

The number of VSAM buffer activities (GTF F61 records) that were not VSAM traces for the IMS full-function database.

UNKNOWN

The number of records other than those listed under one of VSAM request types or NOT IMS DB.

UNKNOWN TYPE

GTF trace records with an event ID that does not match any record types that IMS Buffer Pool Analyzer processes (440 - Buffer Pool Analyzer records, F4F - IMS OSAM records, and F61 - VSAM records). There should be no records in this category. If the report indicates the presence of records, investigate the event ID that is associated with the records, determine the source of the record type, and disable recording the records. For assistance, contact IBM® Software Support.

LOST RECORDS

GTF logs the number of records that were discarded because of insufficient buffer space. The number of records shows how many occurrences of lost records were recorded. When present, the actual number of records that were discarded is also listed.

LOST BLOCKS

GTF logs the number of blocks that were discarded because of insufficient buffer space. The number of records shows how many occurrences of lost blocks were recorded. When present, the actual number of blocks that were discarded is also listed.