On Tue, 3 Mar 2009 16:22:50 -0500 Scott Rowe wrote
>I question your logic with regard to BUFNI. If the access pattern is truely >dynamic, then the ideal would be to have space for the index sets and all of >the sequence sets, so that it never reads an index CI more than once. I have >done this on many occasions to save huge amounts of time. You may be right on this. I am primarily a COBOL individual and am thinking in NSR terms as in the following from VSAM Demystified page 75 on NSR Then, for optimum performance, the number of index buffers should at least equal the number of high-level index set CIs plus one per string. This makes the entire high-level index set and one sequence set CI per string in virtual storage. Table 2-6 shows how adding index buffers improves performance. The elapsed time can vary according to the system workload. Note that additional index buffers are not use(sic) for more than one sequence set buffer per string. But I don't find anything in LSR (or BLSR or SMB for that matter) that specifically says that it will load more than one sequence set CI per string. The application uses an ALC subroutine and neither I nor my customer ( one outfit writes it, we beta it, and someone else uses it in production) have the source to any of it. I am trying to dig through the dump but cannot seem to find the VSAM Control Blocks info that I think used to be in DFSMS Using Data Sets. A pointer to same would be VERY much appreciated, I like to dig ..... If any of the VSAM Demystified authors are listening, page 235 at the end of Table 4-3 VSAM Data Set Parameters and Processing Options would be a LOVELY place for such a reference pointer....sigh! ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
