Hi All,
We are looking to improve the performance of a COBOL program that processes 2
VSAM files. The first file is the I/P file and every record read from the input
VSAM file is searched for a matching record in the other file and a report is
written. The program also applies some business rules while comparing each
matching record.
The I/P file is read sequentially while the other file is read in a skip
sequential basis. The test files that were used had 32M records each while
production files have 110M records each.
Attached is the strobe report from the execution of the test job. The test job
takes nearly 7 CPU minutes and was profiled to capture about 1 CPU minute of
execution time.
We are attempting to optimize the VSAM access to these files as it is seen to
take more than 50% of the CPU consumed by this job.
In the 'Attribution of CPU execution time' section, we see that the major
contributors are the components 'QSAM INIT I/O & EXITS' (Module IGZEQBL) and
PARTITION COMMUNICATION.
Could you please help us understand:
1.What these components are
2.Why is QSAM access used instead of VSAM I/O access.
3.What needs to be done to reduce the CPU consumption by these components.
Thank you
Arun
------------------------------------------------------------------------------------------------------------------------------------------------------------------
1Strobe* PERFORMANCE PROFILE PROGRAMA
01/02/2018 PAGE 42
- #ACE ** ATTRIBUTION OF CPU EXECUTION TIME
**
-.COBLIB IGZCPCO IGZEVIO VSAM INPUT/OUTPUT
---------------------------WAS INVOKED BY---------------------
-----------------VIA----------------------- CPU TIME %
XACTION MODULE SECTION DESCRIPTION MODULE
SECTION DESCRIPTION SOLO TOTAL
.LELIB CEEBINIT LE/370 BATCH INIT/TERM
.32 .32
.LELIB CEEBINIT LE/370 BATCH INIT/TERM IGZEQBL
QSAM INIT I/O & EXITS 1.93 1.93
XACTION MODULE SECTION LOCATION LINE SOURCE TEXT MODULE
SECTION DESCRIPTION
PROGRAMA PROGRAMA 003522
1.30 1.30
----- -----
3.55 3.55
-.VSAM IDA019L1 VSAM RECORD MANAGEMENT
---------------------------WAS INVOKED BY---------------------
-----------------VIA----------------------- CPU TIME %
XACTION MODULE SECTION DESCRIPTION MODULE
SECTION DESCRIPTION SOLO TOTAL
.LELIB CEEBINIT LE/370 BATCH INIT/TERM IGZEQBL
QSAM INIT I/O & EXITS 1.84 1.84
.LELIB CEEBINIT LE/370 BATCH INIT/TERM IGZEQBL
CURRMEM QSAM INIT I/O & EXITS 4.34 4.38
.LELIB CEEBINIT LE/370 BATCH INIT/TERM IGZEQBL
DVFILE QSAM INIT I/O & EXITS .03 .03
.LELIB CEEBINIT LE/370 BATCH INIT/TERM IGZEQBL
PREVMEM QSAM INIT I/O & EXITS 22.48 22.51
XACTION MODULE SECTION LOCATION LINE SOURCE TEXT MODULE
SECTION DESCRIPTION
PROGRAMA PROGRAMA 003522 IGZCPCO
CURRMEM PARTITION COMMUNICATION 4.15 4.19
PROGRAMA PROGRAMA 003522 IGZCPCO
IGZEVIO VSAM INPUT/OUTPUT .57 .57
PROGRAMA PROGRAMA 003522 IGZCPCO
PREVMEM PARTITION COMMUNICATION 16.80 16.80
----- -----
50.22 50.32
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