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DB2 - Problembeschreibung

Problem IC83287 Status: Geschlossen

PERFORMANCE PROBLEM WHEN DB2READLOG API CHECKING CONTENT OF REGISTER
VARIABLE.

Produkt:
DB2 FOR LUW / DB2FORLUW / 970 - DB2
Problembeschreibung:
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-Zusammenfassung:
**************************************************************** 
* 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:
verfügbare FixPacks:
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

Lösung
The problem is fix in DB2 version 9.7 fixpack 7.
Workaround
keiner bekannt / siehe Local-Fix
Weitere Daten
Datum - Problem gemeldet    :
Datum - Problem geschlossen :
Datum - der letzten Änderung:
10.05.2012
20.10.2012
20.10.2012
Problem behoben ab folgender Versionen (IBM BugInfos)
9.7.FP7
Problem behoben lt. FixList in der Version
9.7.0.7 FixList