The performance of ALTIBASE HDB is dramatically degraded after upgrading AIX OS from version 5.3 to version 6.1.
1. Observed a state of Service Thread of ALTIBASE HDB by using "procstack" utility of AIX.
2. Found out that built-in function - sysdate() - of ALTIBASE HDB was causing the performace degradation.
3. sysdate() function of ALTIBASE HDB triggers a system-call to "localtime_r()" and it causes the performance degradation. We confirmed the difference between AIX 5.3 and 6.1 with an AIX support engineer.
Performance bottleneck occurs depending on the setting of TimeZone in AIX 6.1. To work around this AIX issue, the default TimeZone setting has to be changed to Local TimeZone based on Posix standard.