Clark,
I don't know where it is written up, but it has been this way as long as I
can remember, which is 5 minutes when I go to the shop, and a bit longer for
IDCAMS.
Following example look at the CISZ(32768) versus the physical record size
(16384). Physical record size is the block size used for each record on the
track, so each CI uses two blocks or records and can span a track boundary.
DATA ------- HAWKINS.KSDS.DATA
IN-CAT --- CATALOG.VHDSUSR
HISTORY
DATASET-OWNER-----(NULL) CREATION--------2018.019
RELEASE----------------2 EXPIRATION------0000.000
ACCOUNT-INFO-----------------------------------(NULL)
PROTECTION-PSWD-----(NULL) RACF----------------(NO)
ASSOCIATIONS
CLUSTER--HAWKINS.KSDS
ATTRIBUTES
KEYLEN----------------44 AVGLRECL-------------435
BUFSPACE----------530432 CISIZE-------------32768
RKP--------------------0 MAXLRECL------------2040
EXCPEXIT----------(NULL) CI/CA-----------------22
SHROPTNS(3,3) SPEED UNIQUE NOERASE INDEXED
NOWRITECHK UNORDERED NOREUSE
NONSPANNED
STATISTICS
REC-TOTAL--------------0 SPLITS-CI--------------0
EXCPS------------------0
REC-DELETED------------0 SPLITS-CA--------------0
EXTENTS----------------1
REC-INSERTED-----------0 FREESPACE-%CI----------0
SYSTEM-TIMESTAMP:
REC-UPDATED------------0 FREESPACE-%CA----------0
X'0000000000000000'
REC-RETRIEVED----------0 FREESPC-----------720896
ALLOCATION
SPACE-TYPE------CYLINDER HI-A-RBA----------720896
SPACE-PRI--------------1 HI-U-RBA---------------0
SPACE-SEC--------------1
VOLUME
VOLSER------------HDSUS5 PHYREC-SIZE--------16384
HI-A-RBA----------720896 EXTENT-NUMBER----------1
DEVTYPE------X'3010200F' PHYRECS/TRK------------3
HI-U-RBA---------------0 EXTENT-TYPE--------X'40'
VOLFLAG------------PRIME TRACKS/CA-------------15
EXTENTS:
LOW-CCHH-----X'00060000' LOW-RBA----------------0
TRACKS----------------15
HIGH-CCHH----X'0006000E' HIGH-RBA----------720895
Ron
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On
Behalf Of Clark Morris
Sent: Tuesday, January 16, 2018 9:01 AM
To: [email protected]
Subject: Re: [IBM-MAIN] VSAM Performance - CPU reduction
[Default] On 16 Jan 2018 06:54:52 -0800, in bit.listserv.ibm-main
[email protected] (Ron hawkins) wrote:
>Tim,
>
>Things changed a couple of decades ago.
>
>VSAM physical block is not always the same as the CISZ.
>
>32K CISZ does not waste any space on the track.
Where is this written up? Being retired, I missed this and didn't realize
this was true on the OS390 system I worked on in the 1990s.
Clark Morris
>
>Ron
>
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