IBM SC34-6814-04 Server User Manual


 
Reading journal records offline
Access to journaled data in log streams is provided through an MVS subsystem
interface (SSI), LOGR. Your existing user programs can read the general log
streams, providing you specify, in your batch job JCL, the SUBSYS parameter and
supporting options on the DD for log streams. By specifying the LOGR subsystem
name on the SUBSYS parameter, you enable LOGR to intercept data set open and
read requests at the SSI, and convert them into log stream accesses.
Depending on the options specified on the SUBSYS parameter, general log stream
journal records are presented either:
v In the record format used at CICS/ESA 4.1 and earlier, for compatibility with
older utilities (selected by the COMPAT41 option), or
v In the CICS Transaction Server for z/OS format (introduced at CICS Transaction
Server for OS/390, Version 1 Release 1), for newer or upgraded utilities needing
to access log record information.
CICS system log records are only available in the CICS Transaction Server for
z/OS format, so you must ensure that any utilities that handled system log records
in releases prior to CICS Transaction Server for OS/390, Version 1 Release 1 are
converted to handle this format.
Journal records can be read offline by user-written programs. You can generate the
DSECTs that such programs need by including certain statements in the program
code, as follows:
v For records in the CICS Transaction Server for z/OS format on general logs,
offline user-written programs can map journal records by including an INCLUDE
DFHLGGFD statement. This generates the assembler version of the DSECT.
v For records formatted with the COMPAT41 option, offline user-written programs
can map journal records by issuing the DFHJCR CICSYST=YES statement,
which results in the DFHJCRDS DSECT being included in the program.
The DSECT thus generated is identical to that obtained for CICS programs by
the COPY DFHJCRDS statement, except that the fields are not preceded by a
CICS storage accounting area. The DSECT is intended to map journal records
directly in the block, rather than in a CICS storage area.
The following section describes the structure of CICS Transaction Server for
z/OS-formatted journal records. The structure and content of CICS/ESA 4.1-format
journal records are described in “Structure and content of COMPAT41-format journal
records” on page 729.
Structure and content of CICS Transaction Server for z/OS format
journal records
SMF records
The following description does not apply to journal records written to an SMF data
set. These are described on page “Format of journal records written to SMF” on
page 737.
General logs (that is, those containing forward-recovery logs, auto-journals, and
user journals) can be presented in the format introduced at CICS Transaction
Server for OS/390, Version 1 Release 1. Each journal record in these logs, if
presented in the newer format, contains more information than in the equivalent
journal record presented in the CICS/ESA 4.1 format.
712 Customization Guide