FWIW This VSAM index issue is most likely due to CI/CA splits. I would suggest unloading/deleting/reloading the complete VSAM cluster (if necessary ALTERing the original VSAM cluster to some temp other names instead of deleting it, after the unload and as a fall-back) to fix this. A FREESPACE(ca,ci) on reload is unlikely to achieve anything other than to waste DASD space. A dump of its current VSAM index would show what the actual problem is.
On 31/08/2020 04:16, Mike Schwab wrote: > 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 > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
