Author: aswinir
Subject: High CPU consumption Job using IAM files as input
Posted: Thu Dec 01, 2016 8:28 pm (GMT 5.5)
I have a high CPU consumption job that uses IAM files as input. When profiled the job using strobe, it says âInnovation Access Method (IAMBPC01)â takes 33.36 % of CPU SOLO time and VSAM Record Management takes 27.28 % of CPU Solo time in the most extensively used procedures.
The program is driven by an IAM file which has 10 million records. This reads another two IAM files in random mode. One file has close to 70 K records and the other file has nearly 90 million records. But from the 90 million records, we fetch only half of its total count (i.e., 45 million) based on specific record type. Since these records that are in need are not contiguous, sequential or skip sequential reads are not of much significant as it would take more CPU.
Would like to understand what IAMBPC01 section is and why nearly 33 % is utilized.
Please find the strobe report for reference.
Listcat report is attached for reference. Would also like to know what is âSTORAGE REQUIRED FOR COMPRESSED PRIME INDEXâ and âNUMBER OF IAM DATA BLOCKSâ
Subject: High CPU consumption Job using IAM files as input
Posted: Thu Dec 01, 2016 8:28 pm (GMT 5.5)
I have a high CPU consumption job that uses IAM files as input. When profiled the job using strobe, it says âInnovation Access Method (IAMBPC01)â takes 33.36 % of CPU SOLO time and VSAM Record Management takes 27.28 % of CPU Solo time in the most extensively used procedures.
The program is driven by an IAM file which has 10 million records. This reads another two IAM files in random mode. One file has close to 70 K records and the other file has nearly 90 million records. But from the 90 million records, we fetch only half of its total count (i.e., 45 million) based on specific record type. Since these records that are in need are not contiguous, sequential or skip sequential reads are not of much significant as it would take more CPU.
Would like to understand what IAMBPC01 section is and why nearly 33 % is utilized.
Please find the strobe report for reference.
Listcat report is attached for reference. Would also like to know what is âSTORAGE REQUIRED FOR COMPRESSED PRIME INDEXâ and âNUMBER OF IAM DATA BLOCKSâ