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  1. Core Server
  2. SERVER-10553

losing indexes on secondaries

    • Type: Icon: Bug Bug
    • Resolution: Done
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 2.2.3
    • Component/s: None
    • Labels:
      None
    • Environment:
      ubuntu
    • ALL

      I'm in the process of upgrading from 2.2.3 to 2.4.5. I upgraded one cluster last week and another this week, and both times, when I elected the new primary, it turned out to be missing all the indexes for at least a couple of collections.

      Here's a collection on the old primary:

      mongodata3:SECONDARY> db["app_22d9b327-2c33-4296-bb50-48b6917b356f:_Installation"].stats()
      {
              "ns" : "appdata53.app_22d9b327-2c33-4296-bb50-48b6917b356f:_Installation",
              "count" : 2962834,
              "size" : 1011357036,
              "avgObjSize" : 341.3478568154679,
              "storageSize" : 1164914688,
              "numExtents" : 18,
              "nindexes" : 8,
              "lastExtentSize" : 307515392,
              "paddingFactor" : 1.0000000002533629,
              "systemFlags" : 1,
              "userFlags" : 0,
              "totalIndexSize" : 1238917456,
              "indexSizes" : {
                      "_id_" : 123800992,
                      "installationId_1_deviceToken_1" : 236245520,
                      "installationId_1" : 231871360,
                      "deviceToken_1" : 67214896,
                      "_updated_at_1" : 142589440,
                      "_created_at_1" : 96967360,
                      "timeZone_1__created_at_1" : 236220992,
                      "channels_1__created_at_1" : 104006896
              },
              "ok" : 1
      }
      

      and on the new one:

      mongodata3:PRIMARY> db["app_22d9b327-2c33-4296-bb50-48b6917b356f:_Installation"].stats()
      {
              "ns" : "appdata53.app_22d9b327-2c33-4296-bb50-48b6917b356f:_Installation",
              "count" : 2962834,
              "size" : 861644152,
              "avgObjSize" : 290.81755913426133,
              "storageSize" : 965894144,
              "numExtents" : 18,
              "nindexes" : 1,
              "lastExtentSize" : 256282624,
              "paddingFactor" : 1.0000000002360774,
              "systemFlags" : 1,
              "userFlags" : 0,
              "totalIndexSize" : 152073600,
              "indexSizes" : {
                      "_id_" : 152073600
              },
              "ok" : 1
      }
      

      Not sure how many collections this has happened to, I only found these by visually scanning the logs for high nscanned numbers. I have tried grepping the logs for any indication of an index getting dropped, but there is nada.

      I did run a compaction on all the collections a while back, but I checked for interrupted index builds at the time and didn't see anything. That's the only thing I can think of though, am I missing anything?

            Assignee:
            Unassigned Unassigned
            Reporter:
            charity@parse.com charity majors
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              Created:
              Updated:
              Resolved: