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  1. Core Server
  2. SERVER-16122

PRIMARY down on sharded cluster - downtime

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    • Icon: Bug Bug
    • Resolution: Incomplete
    • Icon: Major - P3 Major - P3
    • None
    • 2.4.12, 2.6.5
    • Sharding
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      I can replicate this behaviour when running mongos on top of single replicaset (PRIMARY, SECONDARY, ARBITER), then I run simple ruby script (https://gist.github.com/lowang/5fc24c6e40b03a613d2b - using original mongo gem, with secondary_preferred) issuing 2 read queries per second to sharded collection.
      Then I simulate PRIMARY server problem by issuing "halt -n -f" on it's virtual machine. After few seconds script cannot get results.

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      I can replicate this behaviour when running mongos on top of single replicaset (PRIMARY, SECONDARY, ARBITER), then I run simple ruby script ( https://gist.github.com/lowang/5fc24c6e40b03a613d2b - using original mongo gem, with secondary_preferred) issuing 2 read queries per second to sharded collection. Then I simulate PRIMARY server problem by issuing "halt -n -f" on it's virtual machine. After few seconds script cannot get results.

    Description

      I've got downtime (read queries cannot complete) when PRIMARY is down in sharded cluster.
      It takes from about 20-30s (original mongo gem),
      however original mongo gem is not a problem as I can't issue a query during that time while connecting to mongos directly with mongo client.
      Upgrading to mongo 2.6 didn't improve downtime at all.

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            ramon.fernandez@mongodb.com Ramon Fernandez Marina
            lowang Przemek Wroblewski
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