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  1. Core Server
  2. SERVER-94611

Update SHARDING_FILTER logic to support non-simple collation sharding

    • Type: Icon: Task Task
    • Resolution: Unresolved
    • Priority: Icon: Major - P3 Major - P3
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    • Query Optimization

      SPM-1930 will permit sharding with collation.

      Queries which specify (a superset of) the shard key in equalities (e.g., sharded on

      {a:1}

      , query of

      {a:"foobar"}

      ) can normally be targeted to a single shard. However, if the query collation does not match the sharding collation, this is not possible.

      Prior to the fix for SERVER-94315 QueryPlannerParams::fillOutPlannerParamsForExpressQuery erroneously cleared INCLUDE_SHARD_FILTER in this case, leading to a query executing on multiple nodes, but with no shard filtering, leading to potential duplicate results from orphans.

      At the time of SERVER-94315, prior to SPM-1930, the only possible sharding collation was simple. Once SPM-1930 changes this, QueryPlannerParams::fillOutPlannerParamsForExpressQuery must be updated to reflect this.

            Assignee:
            Unassigned Unassigned
            Reporter:
            james.harrison@mongodb.com James Harrison
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              Created:
              Updated: