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  1. JGroups
  2. JGRP-1051

TimeScheduler: replace use of ScheduledThreadPoolExecutor with ConcurrentSkipListMap

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Details

    • Feature Request
    • Resolution: Done
    • Major
    • 2.11
    • None
    • None
    • 0
    • 0% 0%

    Description

      TimeScheduler currently extends ScheduledThreadPoolExecutor, which uses a DelayQueue for keeping an ordered list of tasks (ordered by their execution times).
      DelayQueue doesn't provide good speed, e.g. (IIRC) remove() requires a linear list scan.

      ConcurrentSkipListMap however provides O(log) cost for get(), put(), remove() and containsKey(). Attached is a cursory impl of TimeScheduler based on ConcurrentSkipListMap. It is faster than the old version.

      Since ConcurrentSkipListMap requires JDK 1.6, we cannot use this in 2.6.x. It can be used in 3.0 only, or perhaps - after a discussion on the mailing list - in 2.9...

      Attachments

        1. timer.zip
          24 kB
        2. TimeScheduler.java
          15 kB
        3. TimeScheduler.patch
          4 kB

        Issue Links

          blocks

          Task - Represents a small unit of work that is not end-user facing. ISPN-231 Replace use of ScheduledThreadPoolExecutor if affected by contention

          • Minor - To be worked after urgent, high, and medium priorities are resolved. This term is chosen when the severity of the issue is low, or the complexity or effort to correct it may be higher, relatively speaking. For low priority issues, known workarounds exist or are not needed due to the trivial effort needed to address the issue.
          • Closed
          is related to

          Bug - A problem that impairs or prevents the functions of the product. JGRP-1062 TimeScheduler: if a periodic task throws an exception, task is not run again

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Resolved
          relates to

          Task - Represents a small unit of work that is not end-user facing. JGRP-1099 NAKACK: don't send retransmission requests individually

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Resolved

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              Dates

                Created:
                Updated:
                Resolved: