|
Problem IC83287
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Status: Closed |
PERFORMANCE PROBLEM WHEN DB2READLOG API CHECKING CONTENT OF REGISTER VARIABLE. |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
The way db2ReadLog API checking content of register variable on
disk may cause performance impact, since db2ReadLog may not
cache the value of register variable in memory. Please note that
the register variable will be checked regardless of it is set or
not set.
One of the victim for this non-cached register variable is
application that invokes db2ReadLog API, for eg, SQL-Replication
capture or Q-Replication capture.
To verify this performance problem, stack trace is helpful. The
command "db2pd -stack all -repeat" or "db2pd -stack <eduid>" can
generate stack files. The generated stack files can be found
under DIAGPATH.
Below is a sample stack we have found.
_global_lock_common
_rec_mutex_lock
_getpwnam_shadow_r
_posix_getpwnam_shadow_r
getpwnam_r
sqloGetUserAttribByName
EnvGetHomePath
EnvKeyName
EnvPrfOpen
sqloGetEnvUnCached
sqlp_AsyncLogReadAPI
sqlpReadLogInternalAPI
sqlpReadLogDRDA
sqlerKnownProcedure
sqlerCallDL
The above stack is collected from db2agent thread which is
serving for application calling db2ReadLog.
The function sqloGetEnvUnCached is the key point. If
sqloGetEnvUnCached can be observed for several times in multiple
iterations of stack trace, then this performance problem is
being hit. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Applications calling db2ReadLog API. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Update to DB2 version 9.7 fixpack 7 or later fixpacks. *
**************************************************************** |
| Local Fix: |
|
| available fix packs: |
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 9 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
The problem is fix in DB2 version 9.7 fixpack 7. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 10.05.2012
20.10.2012
20.10.2012 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP7
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.7
|
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