|
Problem IC65171
|
Status: Closed |
DECOMMIT OF "APPLICATION SHARED MEMORY" AS OF SOLARIS 10 UPDATE 4 CANCAUSE MEMORY CORRUPTION / DB2 INSTANCE TRAP |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
SOLARIS 10 UPDATE 4 includes an enhancement - multiple page size
support for pagable shared memory - which impacts DB2.
Solaris will choose the largest page size appropriate for
pagable shared memory allocations.
DB2 takes advantage of this for Automatic Database Shared
Memory, but uses a maximum 64K page size (this is documented).
This maximum page size is required as DB2 decommits memory in
multiples of 64K.
This APAR will address the Application Memory area which
currently uses the default page size chosen by Solaris.
This memory area also grows and shrinks (is decommited) in
multiples of 64K.
Given the typical sizes of Application Memory shared
allocations, Solaris will choose a page size of 4MB.
Whenever DB2 decommits a portion of the large page, the entire
page may be reused for other purposes on the system.
This could result in perceived memory corruption and a DB2
instance crash, since DB2 is still expecting other ranges on the
large page to be valid.
However, the nature of the decommit operation on Solaris is such
that if DB2 references memory on the page before it is
reassigned, the memory page returns to it's previous state and
the ranges continue to be valid.
Given that all of "in-use" Application Memory is continually
accessed, it would be extremely rare for the memory page to be
reused by the operating system, and this problem has not been
seen by customers.
The APAR is resolved by changing Application Memory to use a
maximum 64K pagesize on Solaris, similar to AUTOMATIC Database
Memory. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Systems running DB2 on Solaris *
****************************************************************
* PROBLEM DESCRIPTION: *
* See error description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to a level of DB2 containing the APAR *
**************************************************************** |
| Local Fix: |
|
| available fix packs: |
DB2 Version 9.7 Fix Pack 2 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
Problem first fixed in DB2 Version 9.7 Fix Pack 2 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 16.12.2009
14.06.2010
14.06.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP2
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.2
|
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