On our HSM MCDS, BCDS, etc, we have 0 for the secondary extent. If we specified TRACK(50000 1) so we get 1 track as the Control Area, 1. How much would the Index size go up? 15X? 2. Wouldn't CAs be reused a lot more frequently, since you only have to get 1 track empty instead of 15? 3. Which would be better for an end user? 4. How would throughput be affected?
On Tue, Mar 15, 2016 at 6:07 AM, John Eells <[email protected]> wrote: > Norbert Friemel wrote: > <snip> >> >> >> CA_RECLAIM? >> http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/dgt2d4a0/2.5.3.3 > > <snip> > > Norbert beat me to it (smile). The key to this being useful is that you > have empty CAs to reclaim. One could have a pathological application that > left one record per CA behind after deleting the rest, so that no CAs ever > emptied out to be reclaimed, for example. Or, one could have an even *more* > pathological application that wrote a lot of records into specific key > ranges, deleted them all (causing reclaims) and then rewrote a lot of > records into the same key ranges, causing CA reclaim/CA allocation thrashing > to the detriment of performance. > > That said, it's very likely that using CA Reclaim will get you out of the > reorg business, permanently, with no ill effects, for all of your KSDSs. CA > Reclaim is available on all supported releases now, but I have heard of only > one pathological application so far. Of course, it was one of ours here at > IBM. (You can't make this stuff up.) > > -- > John Eells > IBM Poughkeepsie > [email protected] > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
