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  1. Core Server
  2. SERVER-22264

First Readconcern majority query hangs

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    • Icon: Bug Bug
    • Resolution: Done
    • Icon: Major - P3 Major - P3
    • None
    • 3.2.1
    • Querying, Replication
    • None
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      Reproduced this consistently a few times in AWS:

      config:

      • 3 member replicaSet
      • 2 delayed secondaries (set 3600)
      • m3.medium
      • version 3.2.1

      steps (done via mongo shell):
      1. enableMajorityReadConcern
      2. insert something
      3. query inserted document on primary using "local" readConcern as a sanity check
      4. query inserted documented with readConcern majority

      expected results: the query should hang for a very long time (at least it happen to me after recreating this environment multiple times in AWS via CloudManager)

      Additional observations:
      The query hanged indefinitely for me when delay was 3600s. I was able to get the query to complete on 3.2.0 with delay set to 60s. The first query hanged for ~30s and returned no results as expected. Subsequent queries (on updates performed on the document) with this different configuration after the first returned without observed delay.

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      Reproduced this consistently a few times in AWS: config: 3 member replicaSet 2 delayed secondaries (set 3600) m3.medium version 3.2.1 steps (done via mongo shell): 1. enableMajorityReadConcern 2. insert something 3. query inserted document on primary using "local" readConcern as a sanity check 4. query inserted documented with readConcern majority expected results: the query should hang for a very long time (at least it happen to me after recreating this environment multiple times in AWS via CloudManager) Additional observations: The query hanged indefinitely for me when delay was 3600s. I was able to get the query to complete on 3.2.0 with delay set to 60s. The first query hanged for ~30s and returned no results as expected. Subsequent queries (on updates performed on the document) with this different configuration after the first returned without observed delay.

    Description

      The first query with readConcern majority will hang for a long time when there is significant replication lag/delay

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            Unassigned Unassigned
            dylan.tong Dylan Tong
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              Updated:
              Resolved: