Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-39234

Sharding an empty collection in mixed-shard version configurations may leave all chunks on the primary shard

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: 4.0.5
    • Fix Version/s: 4.0.6, 4.1.8
    • Component/s: Sharding
    • Labels:
      None
    • Backwards Compatibility:
      Fully Compatible
    • Operating System:
      ALL
    • Backport Requested:
      v4.0
    • Sprint:
      Sharding 2019-02-11
    • Linked BF Score:
      50

      Description

      In partially upgraded clusters, whose config server is at version 4.0.5 and shards are at pre-4.0.3 (includes 3.6), sharding an empty collection with hashed sharding or performing map/reduce with outputting to an empty collection (with any kind of sharding) will end up placing all chunks on the primary shard of the collection.

      This is not a correctness issue, but it means that the balancer will have to move non-empty chunks later on and thus defeats the purpose of pre-sharding the collection.

        Attachments

          Activity

            People

            • Votes:
              0 Vote for this issue
              Watchers:
              3 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved: