Re: Deleted records

Chuck,

Thank you for the explanation. I had no intent of attempting to operate on
this particular file. To me, QSYS is not a library to be tinkering with.
I had hoped that there was a method to release the deleted records.
Currently, our backup just barely requires a second 3590 cartridge. I had
hoped, by reducing deleted records, to allow the backup to fit on a single
cartridge. There will not be any significant new development. Boss wants
to make backup unattended. Freeing deleted records seemed like a
possibility. RCLDBXREF with *CHECK reported no problems were found.

John McKee


On Mon, Jun 30, 2014 at 12:03 PM, CRPence <CRPbottle@xxxxxxxxx> wrote:

On 30-Jun-2014 11:33 -0500, John McKee wrote:

A few weeks ago, I ran DSPFD on production (well used to be)
libraries. Found a lot of deleted records and reorganized those
files. They were set to reuse deleted records.

Ran the CL again on all files in all libraries.

The files QADB* in QSYS should be explicitly omitted from such
processing. The effects from issuing Reorganize Physical File Member
(RGZPFM) against those files needs to be expressly evaluated for the
potentially highly negative impact to the system operation; the request to
reorg any of those files should not be on a whim or even a mere consequence
of something akin to a whim due to some algorithm blind to the relevance of
the underlying data and the requirements [for the users and the system] to
have access to that data.

QSYS/QADBIFLD has 678746 records and 361,585 deleted records.

How is space recovered from this file?

The file QADBIFLD is the System Database Cross-Reference (DBXREF) table
of columns; i.e. as physical data, primarily for the SYSCOLUMNS SQL Catalog
VIEW. When any new columns are created, a new record to track that column
is placed in the file QADBIFLD in QSYS; in effect, whenever that column is
deleted, the row representing that column within the catalog is deleted,
and that becomes a deleted record. Thus whenever new file(s) are created,
due to the file QADBIFLD having the Reuse Deleted Records (REUSEDLT)
feature activated, deleted rows will tend toward being utilized instead of
remaining as /deleted/ entries.

The *DBXREF feature enables a data-refresh feature with either the
Reclaim Database Cross-Reference (RCLDBXREF) or the Reclaim Storage
(RCLSTG) features. The refresh is typically the most favorable approach
[over reorg], first because the system is offline thus limiting impacts to
concurrent work, and second because any errors with the data should be
resolved by the request [whereas a reorganize would just move any incorrect
data]; the former command has an option to display if the status of the
DBXREF data is known already by the DBXREF feature, to be incorrect.

--
Regards, Chuck
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