Arun,
in my recent experiences I've got bif improvement using SMB (System Managed
Buffer).
If I'm not wrong both DS are EXTENDED so you could.
Try coding into the DD "AMP=('ACCBIAS=SO')" for the main sequentially read
file and "AMP=('ACCBIAS=DO')" for the second one. At the same time enlarge
the REGION size.
Depending on your HW configuration you could consider using compression on
both DS. It will increase CPU time (or not so much if you've got zEDC) but
could improve elapsed .... depending on CPU contention.
Hope this helps.
Regards.
Massimo
2018-01-06 1:20 GMT+01:00 Arun Venkatratnam <[email protected]
>:
> 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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