IV86730: PERFORMANCE REGRESSION WHEN USING OLSON TIMEZONE FORMAT APPLIES TO AIX 7100-04

APAR status

• Closed as program error.

Error description

• **************************************************************
  * USERS AFFECTED:
    * Systems running the AIX 7100-04 Technology Level
    * with bos.rte.libc at the 7.1.4.1 level.
    **************************************************************
    * PROBLEM DESCRIPTION:
    * A significant performance regression was introduced in the
    * time related APIs when the Olson timezone format is used.
    * (ex: "TZ=America/Sau_Paulo")
    *
    * Calls to time functions such as tzset(), mktime(), and
    * localtime() may take significantly longer to complete,
    * which can compound and have an impact on application
    * performance, depending on how the application uses these
    * function calls.
    **************************************************************
    * RECOMMENDATION:
    * Install APAR IV86730.
    * Prior to fix availability, an interim fix is available from
    * either
    * ftp://aix.software.ibm.com/aix/ifixes/iv86730/
    * https://aix.software.ibm.com/aix/ifixes/iv86730/
    * Installation of the ifix requires a reboot.
    **************************************************************
  

Local fix

• Using POSIX timezone format will avoid this issue.
  

Problem summary

•   **************************************************************
    * USERS AFFECTED:
    * Systems running the AIX 7100-04 Technology Level
    * with bos.rte.libc at the 7.1.4.1 level.
    **************************************************************
    * PROBLEM DESCRIPTION:
    * A significant performance regression was introduced in the
    * time related APIs when the Olson timezone format is used.
    * (ex: "TZ=America/Sau_Paulo")
    *
    * Calls to time functions such as tzset(), mktime(), and
    * localtime() may take significantly longer to complete,
    * which can compound and have an impact on application
    * performance, depending on how the application uses these
    * function calls.
    **************************************************************
    * RECOMMENDATION:
    * Install APAR IV86730.
    * Prior to fix availability, an interim fix is available from
    * either
    * ftp://aix.software.ibm.com/aix/ifixes/iv86730/
    * https://aix.software.ibm.com/aix/ifixes/iv86730/
    * Installation of the ifix requires a reboot.
    **************************************************************
  

Problem conclusion

• Timezone function tzset() was calling stat() on every call to
  check for updates to the timezone rules file.  This stat() call
  is costly and was impacting the performance of all timezone
  functions.
  .
  Added a limit to only call stat() a maximum of once every
  minute.
  

Temporary fix

•   *********
    * HIPER *
    *********
  

Comments

• 6100-09 - use AIX APAR IV86773
  7100-04 - use AIX APAR IV86730
  7200-01 - use AIX APAR IV86755
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  IV86755 IV86773 IV86890 IV86902 IV87788 IV87789

Fix information

• Fixed component name

  AIX V7.1

• Fixed component ID

  5765H4000

Applicable component levels

• R710 PSY U875349

     UP16/12/12 I 1000 «