Ricc, Yes the COFxxxxx macros must be used by the application to benefit from the VLF cache - obviously CSV does this on our behalf for LLA program management. Unless the PDS members you are referring to is "LOAD"ed, there is little VLF can help with actually caching the member contents without changes to the application.
You can measure VLF class performance using SMF-41 records. You can investigate performance benefits for LLA versus PGM fetch for individual programs by using the CSVLLIX1 exit. (I believe you are an MXI G2 customer, hence you can use the "VLF" and "LLA" commands to see the performance data interactively without having to author your own SMF41 post-processing report or CSVLLIX1 exit.) Rob Scott Lead Developer Rocket Software 275 Grove Street * Newton, MA 02466-2272 * USA Tel: +1.617.614.2305 Email: rsc...@rs.com Web: www.rocketsoftware.com -----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Ricc Harding Sent: 12 January 2011 17:44 To: IBM-MAIN@bama.ua.edu Subject: Re: DLF - DLFCLASS Using DLF for PDS data? Graham; Yes, it could be converted to a PDSE. It does not appear that even VLF can be used "simply" by creating a class for the object and then activating that parmlib member. It appears that the application must be modified to use the VLF macros to define and connect to the object. It is vendor product code that is accessing the dataset so changing code is not possible. I am assuming from that sparse response on this list that VLF/DLF expertise is still being "grown". An interesting, funny, sidelight is one of their previous system programmers had put SYS1.IMAGELIB in the linklist "to take advantage of the VLF/LLA performance improvement. I don't have any data as to whether there were any actual performance improvements for SYS1.IMAGELIB doing this. I would be able to tell in one day if there were improvements doing this for the customer PDS (and no it does not contain any executable code). I have read everything that is available not on VLF install and planning and it is still ambiguous on if it can be used to cache datasets for general across the board access. any info appreciated. ---------------------------------------------------------------------- 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
