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Problem IT06008
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Status: Closed |
AIX MULTIHEAP, BUCKETS MALLOC OPTIONS CAUSE REGRESSION IN PRIVATE VIRTUAL MEMORY USAGE |
| product: |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 |
| Problem description: |
Certain malloc options were inadvertently left in place for DB2
10.5 GA and up. The multiheap and buckets options were meant to
be temporary during development and should be removed. These
options cause excessive fragmentation and private virtual memory
usage within DB2. However, they do not impact normal operations
as they do not normally result in additional system memory usage
- it is only process address space that is consumed.
Symptoms are visible only when diagnostics are generated or
certain service tools are run:
1. db2pd -memblocks pid=<db2sysc pid> and manual core generation
will commit the excess address space, which will significantly
increase DB2 memory usage, possibly causing system performance
problems.
2. coredumps generated when DB2 aborts may be much larger than
necessary, consuming additional disk space.
Note if MALLOCOPTIONS is still required after this change, it
can be set manually, for example
add required options to sqllib/userprofile, as in
export MALLOCOPTIONS=MULTIHEAP:4
add MALLOCOPTIONS to DB2's accepted environment variable list :
db2set DB2ENVLIST=MALLOCOPTIONS (requires db2stop/db2start) |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* DB2 on AIX systems are affected *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Problem first fixed in DB2 Version 10.5 Fix Pack 7 *
**************************************************************** |
| Local Fix: |
add the following line to sqllib/userprofile :
export MALLOCOPTIONS= |
| Solution |
Problem first fixed in DB2 Version 10.5 Fix Pack 7 |
| Workaround |
See Local Fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 09.12.2014
18.02.2016
18.02.2016 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.5.0.7
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