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  1. Core Server
  2. SERVER-50665

Index creation stuck with "Index Build: draining writes received during build"

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    • Type: Question
    • Status: Closed
    • Priority: Minor - P4
    • Resolution: Duplicate
    • Affects Version/s: 4.4.0
    • Fix Version/s: None
    • Component/s: Index Maintenance
    • Labels:
    • Environment:
      CentOS Linux release 8.2.2004, db version v4.4.0

      Description

      Good day,

      I have 4 rows in the test collection:

      {{{ "_id" : ObjectId("5f4ce50e19b13337216dd477"), "test" : 1 }{ "_id" : ObjectId("5f4ce50e19b13337216dd478"), "test" : 2 }{ "_id" : ObjectId("5f4ce50e19b13337216dd479"), "test" : 3 }{ "_id" : ObjectId("5f4ce50e19b13337216dd47a"), "test" : 4 }}}
      

      After running db.test.createIndex({test:1},{background:1}); to create an index, it just hangs. It was hanging for at least a few hours. Here is what I found in the db.currentOp() about this operation:
       

      {{{"type" : "op","host" : "HOSTNAME:27017","desc" : "IndexBuildsCoordinatorMongod-13","active" : true,"currentOpTime" : "2020-08-31T12:11:13.159+00:00","opid" : 8721867,"secs_running" : NumberLong(20),"microsecs_running" : NumberLong(20888590),"op" : "command","ns" : "test.test","command" : {"createIndexes" : "test","indexes" : [{"v" : 2,"key" : {"test" : 1},"name" : "test_1","background" : 1}],"lsid" : {"id" : UUID("07b43083-8ab9-4bcb-8768-919a3f27655f")},"$clusterTime" : {"clusterTime" : Timestamp(1598875647, 409),"signature" : {"hash" : BinData(0,"+/YcdPyQriT8RL1LtFUhxe2BtCE="),"keyId" : NumberLong("6861636045532823556")}},"$db" : "test"},"msg" : "Index Build: draining writes received during build","numYields" : 0,"locks" : {},"waitingForLock" : false,"lockStats" : {"ReplicationStateTransition" : {"acquireCount" : {"w" : NumberLong(6)}},"Global" : {"acquireCount" : {"r" : NumberLong(1),"w" : NumberLong(4)}},"Database" : {"acquireCount" : {"r" : NumberLong(1),"w" : NumberLong(4)}},"Collection" : {"acquireCount" : {"r" : NumberLong(1),"w" : NumberLong(3),"W" : NumberLong(1)}},"Mutex" : {"acquireCount" : {"r" : NumberLong(4)}}},"waitingForFlowControl" : false,"flowControlStats" : {"acquireCount" : NumberLong(3),"timeAcquiringMicros" : NumberLong(1)}}}}
      

      This Index Build: draining writes received during build makes no sense to me since there was no read/writes to the test collection during index creation.

      Also index creation hangs only in non-empty collection. Index creates successfully in empty collection.

      I'm running MongoDB server as a single-node replica set.

      I haven't found any mentions of this message in the google, so I assume it's not a bug, but an issue on my side.

      What might be an issue in this case? I'm out of ideas.

      PS: apologies if I selected wrong Project for this issue/question.

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              Assignee:
              dmitry.agranat Dmitry Agranat
              Reporter:
              bobgubko13@gmail.com Ivan Shcholokov
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