APAR status
Closed as program error.
Error description
scheduleAtFixedRate task that takes very little time to run can encounter a timing window where a duplicate execution occurs immediately after.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM WebSphere Application * * Server ManagedScheduledExecutorService * **************************************************************** * PROBLEM DESCRIPTION: A ManagedScheduledExecutorService * * scheduleAtFixedRate task that takes * * very little time to run might * * intermittently run again immediately * * after. * **************************************************************** * RECOMMENDATION: * **************************************************************** The task is somehow starting (and completing) before its scheduled time and so the computation of the next scheduled execution ends up being the same as the previously scheduled execution, causing the task to run a second time in the very near future, in violation of the fixed rate. Possibly there might have been a slight change to system time that causes this.
Problem conclusion
The computation of fixed-rate was rewritten to first try adding on the fixed-rate amount to the previously scheduled execution time, which it uses if that time is in the future. Otherwise it falls back to computing a next time based on how many fixed-rate executions were missed. The fix for this APAR is targeted for inclusion in fix pack 9.0.5.13. For more information, see 'Recommended Updates for WebSphere Application Server': https://www.ibm.com/support/pages/node/715553
Temporary fix
Comments
APAR Information
APAR number
PH45977
Reported component name
WEBS APP SERV N
Reported component ID
5724H8800
Reported release
900
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2022-04-27
Closed date
2022-06-28
Last modified date
2022-06-28
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
WEBS APP SERV N
Fixed component ID
5724H8800
Applicable component levels
[{"Line of Business":{"code":"LOB45","label":"Automation"},"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.0"}]
Document Information
Modified date:
29 June 2022