>>> Member names. The reason would be that a PDS directory is maintainedin
order,
> and the directory is always kept compressed.
Tom,
Thanks for the info and as mentioned earlier DFSORT has the ability of
sorting the member names in ascending/descending order. Here is a sample
to show just the sorting of pds member names.
//STEP0100 EXEC PGM=IKJEFT01
//SYSTSPRT DD DSN=&&MBRS,DISP=(,PASS),SPACE=(CYL,(5,5),RLSE),
// DCB=(LRECL=80,RECFM=FB,BLKSIZE=0),UNIT=SYSDA
//SYSTSIN DD *
LISTDS 'USERID.PDS' MEMBERS
//*
//STEP0200 EXEC PGM=SORT
//SYSOUT DD SYSOUT=*
//SORTIN DD DISP=SHR,DSN=&&MBRS
//SORTOUT DD SYSOUT=*
//SYSIN DD *
INREC IFTHEN=(WHEN=GROUP,BEGIN=(1,11,CH,EQ,C'--MEMBERS--'),
END=(1,5,CH,EQ,C'READY'),PUSH=(81:ID=1)),
IFTHEN=(WHEN=(1,11,CH,EQ,C'--MEMBERS--',OR,
1,05,CH,EQ,C'READY'),OVERLAY=(81:8X))
SORT FIELDS=(81,1,CH,A,
03,08,CH,D),EQUALS
//*
Thanks,
Kolusu
DFSORT Development
IBM Corporation
IBM Mainframe Discussion List <[email protected]> wrote on
11/20/2015 09:54:59 AM:
> From: Tom Marchant <[email protected]>
> To: [email protected]
> Date: 11/20/2015 09:55 AM
> Subject: Re: Deleting all members of a pds
> Sent by: IBM Mainframe Discussion List <[email protected]>
>
> On Fri, 20 Nov 2015 08:11:08 -0700, Sri h Kolusu wrote:
>
> >>>>Does it at least sort the list in descending order?
> >
> >Descending order of what? member names or Size? Why exactly do you need
to
> >sort the list ? Do you think it would make a difference to the
directory
> >blocks?
>
> Member names. The reason would be that a PDS directory is maintainedin
order,
> and the directory is always kept compressed.
>
> Whenever a member is deleted from a PDS, the following directory
> entries are all
> shifted to the left. Then, if there is enough space at the end of
> that directory
> block, the first entry from the next block is moved to that space,
> and the process
> repeats to the end of the directory.
>
> As a result, there is less I/O if they are deleted starting at the
> end of the directory.
> This is especially true if there are a lot of members in the PDS.
>
> --
> Tom Marchant
>
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