Well a 1, 2, 4, 7, 8, 11, 13, or 14 track index has 1 track CAs, 3, 6, 9, or 12 for a 3 track CA, 5 or 10 for a 5 track CA, 15 tracks or more for a 1 cylinder CA. Details then vary based on key size, FREESPACE(ca ci) values, etc. Assuming reload after backup, delete, define, restore. If you just delete old records then use will go up with free space left by delete but insert doesn't use that space. I.E. time stamp particularly bad primary key.
On Sun, Aug 30, 2020 at 8:07 PM Michael Watkins <0000032966e74d0f-dmarc-requ...@listserv.ua.edu> wrote: > > More efficient in terms of fewer index LEVELs as Tony Thigpen may have been > getting at? I thought the number of LEVELs was contingent on the the size of > the file and the number of CI and CA splits the index component had endured > and not the allocation of contiguous space for the index component on DASD. A > REORG should reduce the number of LEVELs to its smallest possible number, no? > > -----Original Message----- > From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of > Mike Schwab > Sent: Sunday, August 30, 2020 7:48 PM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: Re: Simple VSAM question on sizing INDEX component > > CAUTION: This email originated from outside of the Texas Comptroller's email > system. > DO NOT click links or open attachments unless you expect them from the sender > and know the content is safe. > > CYL(4 1) should leave one cylinder empty. Cylinder CA will result is a more > efficient index. > > On Sun, Aug 30, 2020 at 5:12 PM Lizette Koehler <stars...@mindspring.com> > wrote: > > > > List - > > > > I have a VSAM Dataset that has grown over the years. When it was set > > up - the INDEX space was left to default > > > > I am wondering if it makes sense to override the Track Allocation and > > put it in Cylinders. > > > > We are noticing a little bit of an increase in run time during reorg. > > I was wondering if this might be due to the data set having 3.4GB now. > > > > This file is EA/EF so it can grow > > > > Over 4500 Cylinders on the Data > > > > And the index is using tracks 2 pri and 11 sec - size is now 2.4 MB > > During reorg we offload records to an archive then reload the current > > data back in > > > > This may be something I cannot improve on, just thought I would see if > > there are any insights I am missing. > > > > Process: > > Offload the data to a temp file > > Archive records older than 2 weeks > > Del/Def VSAM dataset > > Reload current records to VSAM dataset > > This runs daily > > > > Thank you > > Lizette > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, send > > email to lists...@listserv.ua.edu 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 > lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu 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 lists...@listserv.ua.edu with the message: INFO IBM-MAIN
