Ron, The defaults have changed;
This is not the best pointer, but it's all I could find with a quick search http://www-01.ibm.com/support/docview.wss?uid=isg1OA01898: "With OW51451, REPRO uses AMDCIPCA (CI per CA) value for BUFND when SHROPT is not 4." Such buffering (BUFND=CI/CA) will make a difference; espcially an elapsed time difference (but also CPU). Best Regards, Yifat -----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Ron Hawkins Sent: יום ד 15 ספטמבר 2010 17:28 To: IBM-MAIN@bama.ua.edu Subject: Re: DFSMS and System Managed Buffering Yifat, Without any other specification, such as BUFSP at define or BFND on the REPRO, IDCAMS without SMB used to default to BUFND of two, and only read one CI at a time. Are you saying the default changed, or changed for Extended Format? I suggested it would not make huge difference for REPRO because the default CISZ for VSAM is 18K or 26K, and a large BUFND would not make a large difference in elapsed time on a small to medium size dataset. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of > Yifat Oren > Sent: Wednesday, September 15, 2010 4:05 AM > To: IBM-MAIN@bama.ua.edu > Subject: Re: [IBM-MAIN] DFSMS and System Managed Buffering > > Tobias, > > The reason you are not seeing the expected savings is that the IDCAMS REPRO > has already set and used the optimal number of data buffers regardless > of the DATACLAS change (so, no change has actually taken place; > optimal buffering was used for both before and after runs). > > You should see the savings when programs that are not taking care of > their VSAM buffering start using these data sets. > > I too think that 1MB is a bit constrictive for direct access LSR > (bias=do) buffering. > > Best Regards, > Yifat > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
