IV87788: PERFORMANCE REGRESSION WHEN USING OLSON TIMEZONE FORMAT APPLIES TO AIX 7100-03 17/01/27 PTF PECHANGE

APAR status

• Closed as program error.

Error description

• **************************************************************
  * USERS AFFECTED:
    * Systems running the AIX 7100-03 Technology Level
    * with bos.rte.libc at the 7.1.3.47 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 IV87788.
    * Prior to fix availability, an interim fix is available from
    * either
    * ftp://aix.software.ibm.com/aix/ifixes/iv87788/
    * https://aix.software.ibm.com/aix/ifixes/iv87788/
    * 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 7100-03 Technology Level
    * with bos.rte.libc at the 7.1.3.47 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 IV87788.
    * Prior to fix availability, an interim fix is available from
    * either
    * ftp://aix.software.ibm.com/aix/ifixes/iv87788/
    * https://aix.software.ibm.com/aix/ifixes/iv87788/
    * 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

APAR Information

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

  IV86730

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

Fix information

• Fixed component name

  AIX V7.1

• Fixed component ID

  5765H4000

Applicable component levels

• R710 PSY U876060

     UP17/02/08 I 1000 «