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  1. Apache Tez
  2. TEZ-4350

Remove synchronized from DAGAppMaster.serviceInit, serviceStart, serviceStop

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Details

    • Improvement
    • Status: Resolved
    • Major
    • Resolution: Fixed
    • None
    • 0.9.3, 0.10.2
    • None
    • None

    Description

      according to AbstractService.serviceInit javadoc

         * This method will only ever be called once during the lifecycle of
   * a specific service instance.
   *
   * Implementations do not need to be synchronized as the logic
   * in {@link #init(Configuration)} prevents re-entrancy.

      moreover, it generates findbugs alerts for every field that is accessed somewhere else in DAGAppMaster in an unsynchronized fashion:

      Code	Warning
IS	Inconsistent synchronization of org.apache.tez.dag.app.DAGAppMaster.webUIService; locked 57% of time
Bug type IS2_INCONSISTENT_SYNC (click for details)
In class org.apache.tez.dag.app.DAGAppMaster
Field org.apache.tez.dag.app.DAGAppMaster.webUIService
Synchronized 57% of the time
Unsynchronized access at DAGAppMaster.java:[line 2623]
Unsynchronized access at DAGAppMaster.java:[line 2623]
Synchronized access at DAGAppMaster.java:[line 568]
Synchronized access at DAGAppMaster.java:[line 569]
Synchronized access at DAGAppMaster.java:[line 578]
Synchronized access at DAGAppMaster.java:[line 656]

      I cannot see any value now in having it synchronized (most probably this wasn't the case 8 years ago at the time of TEZ-537)

      UPDATE: double-checked, AbstractService lifecycle methods are protected with a lock since YARN-530

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        Issue Links

          is related to

          Sub-task - The sub-task of the issue TEZ-537 Add support for session jars and pre-warming of containers to be re-used across a session

          • Major - Major loss of function.
          • Closed

          Sub-task - The sub-task of the issue YARN-530 Define Service model strictly, implement AbstractService for robust subclassing, migrate yarn-common services

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. TEZ-2548 TezClient submitDAG can hang if the AM is in the process of shutting down

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. MAPREDUCE-5298 Move MapReduce services to YARN-117 stricter lifecycle

          • Major - Major loss of function.
          • Closed
          links to

          Web Link GitHub Pull Request #162

          Activity

            People

              abstractdog László Bodor
              abstractdog László Bodor
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                Resolved:

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