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.
The file QADBIFLD is the System Database Cross-Reference (DBXREF)
How is space recovered from this file?
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.
This mailing list archive is Copyright 1997-2015 by MIDRANGE dot COM and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available here. If you have questions about this, please contact