Dave,
Checkout the following APAR.....
Tim Pittson
tpittson AT himail.hcc DOT com
APAR Identifier ...... PN89379 Last Changed..96/10/07
MAXIMUM REDUCTION VALUE OF ADSM DATABASE DOES NOT CHANGE AFTER
ENTRIES ARE DELETED FROM THE DATABASE
Symptom ...... IN INCORROUT Status ........... CLOSED SUG
Severity ................... 2 Date Closed ......... 96/10/07
Component .......... 565511901 Duplicate of ........
Reported Release ......... 210 Fixed Release ............
Component Name ADSM MVS SERVER Special Notice
Current Target Date ..96/11/30 Flags
SCP ...................
Platform ............
Status Detail: ASSIGNMENT - APAR has been assigned to a
programmer.
PE PTF List:
PTF List:
Parent APAR:
Child APAR list:
ERROR DESCRIPTION:
After deleting a large number of entries from the ADSM database,
the maximum reduction value for the db does not change. Q DB F=D
shows the following statistics:
Assigned Capacity (MB): 15,260
Maximum Reduction (MB): 852
%UTIL: 51.3
This means that the database consists of only 7,828 MB of data.
Since the database is mirrored, the physical assigned capacity
(between both copies) is 30,520 MB, with 15,656 MB being used.
This effectively wastes 14,864 MB of space, which is roughly
equal to 5.5 3390-3 DASD volumes.
This represents a significant amount of wasted DASD space. Due
to the size of the database, the dump and load process suggested
in APAR IC08571 is not feasible.
LOCAL FIX:
PROBLEM SUMMARY:
PROBLEM CONCLUSION:
TEMPORARY FIX:
COMMENTS:
The ADSM Server database has a b-tree organization with
internal refrences to index nodes and siblings. The database
grows sequentially from the bginning to end, and pages that
are deleted internally are re-used later when new information
is added. The only utility that can compress the database
so that "gaps" of deleted pages are not present is the database
dump/load utility.
After extensive database deletion occurrs, due to expiration
processing or filespace/volume delete processing, pages in
the "middle" of the space allocated for the database may become
free, but pages closer to the beginning or end of the database
still allocated. To reduce the size of your database sufficient
free pages must exist at the end of the linear database space
that is allocated over your database volumes. A database
dump followed by a load will remove free pages from the
beginning of the database space to minimize free space
fragmentation and may allow the database size to be reduced.
Request 961007122512 has been entered into our requirements
database to request the development of a utility that would
compress fragmented free space and allow your server database
to be reduced without affecting server availability. We will
consider this requirement for a future ADSM release.
MODULES/MACROS:
SRLS:
RTN CODES:
CIRCUMVENTION:
MESSAGE TO SUBMITTER:
>
>From: David C Campbell[SMTP:eacdcc AT EXPEC DOT COM]
>Sent: Tuesday, May 27, 1997 6:53 AM
>To: ADSM-L AT VM.MARIST DOT EDU
>Subject: clean up / reduce DATABASE
>
>I have and old database that was first allocated on MVS in 1994 and has
>grown to 20 gigabytes.
>
>since then we have been reducing the number of nodes by migrating them
>to other severs.
>
>the database is now only 47% used but there is no room for me to REDUCE
>the DB.
>
>is there any way to compress it so i can free up some space?
>
>regards
>Dave Campbell
>
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