How 'bout ..... Flagging the matches that currently require the random read - and instead pass those records thru the 2nd file - both in this random key sequence - that would eliminate all random reads - yes another sort or 2 and another match pass - but in the past I have found the savings of replacing random reads with sequential access is substantial
Chris Hoelscher Technology Architect, Database Infrastructure Services Technology Solution Services 123 East Main Street Louisville, KY 40202 Humana.com (502) 476-2538 or 407-7266 -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Wayne Bickerdike Sent: Sunday, January 7, 2018 4:18 PM To: [email protected] Subject: Re: [IBM-MAIN] VSAM Performance - CPU reduction Quote Apologies. I missed to mention that depending on a record that matches in the 2nd file, there are some random reads that refer back to a previous record as per the business logic. Hence, the second file has to be VSAM. We also see a similar behavior with few other programs that do skip sequential reads on other VSAM files. Unquote So do the two file match and utilise the VSAM (second file) for random read where it's required. You won't tune your way out of this. On Mon, Jan 8, 2018 at 6:03 AM, Gerhard Adam <[email protected]> wrote: > To me it still looks like you don't have enough index buffers. My > calculation suggests you need at least 137 buffers to keep the index > set in memory. > > > > Sent from my iPhone > > > On Jan 7, 2018, at 10:21 AM, Arun Venkatratnam < > [email protected]> wrote: > > > > Ron, > > > > About 80% of the records qualify from the second file. I tried > > running > the job with BUFND of 2 for the second file. It increased the EXCPs > significantly (from strobe report) on the data records for the 2nd > file and the CPU time went over the other runs and the elapsed time also > increased. > The job runs better with higher values of BUFND for the second file. > > > > You had mentioned that the job reads 30 CI for every skip-seq access. > Could you please tell how did you arrive at that number. LISTCAT shows > that for a CISZ of 26KB, there are 30 CI in 1 CA. > > > > > > Thanks > > Arun > > > > -------------------------------------------------------------------- > > -- For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO > > IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send > email to [email protected] with the message: INFO IBM-MAIN > -- Wayne V. Bickerdike ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN The information transmitted is intended only for the person or entity to which it is addressed and may contain CONFIDENTIAL material. If you receive this material/information in error, please contact the sender and delete or destroy the material/information. Humana Inc. and its subsidiaries comply with applicable Federal civil rights laws and do not discriminate on the basis of race, color, national origin, age, disability or sex. Humana Inc. and its subsidiaries do not exclude people or treat them differently because of race, color, national origin, age, disability or sex. English: ATTENTION: If you do not speak English, language assistance services, free of charge, are available to you. Call 1‐877‐320‐1235 (TTY: 711). Español (Spanish): ATENCIÓN: Si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. Llame al 1‐877‐320‐1235 (TTY: 711). 繁體中文(Chinese)：注意：如果您使用繁體中文，您可以免費獲得語言援助 服務。請致電 1‐877‐320‐1235 (TTY: 711)。 Kreyòl Ayisyen (Haitian Creole): ATANSION: Si w pale Kreyòl Ayisyen, gen sèvis èd pou lang ki disponib gratis pou ou. Rele 1‐877‐320‐1235 (TTY: 711). Polski (Polish): UWAGA: Jeżeli mówisz po polsku, możesz skorzystać z bezpłatnej pomocy językowej. Zadzwoń pod numer 1‐877‐320‐1235 (TTY: 711). 한국어 (Korean): 주의: 한국어를 사용하시는 경우, 언어 지원 서비스를 무료로 이용하실 수 있습니다. 1‐877‐320‐1235 (TTY: 711)번으로 전화해 주십시오. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
