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  1. Core Server
  2. SERVER-49214

Add $toHashedIndexKey expression

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Details

    • Fully Compatible
    • v4.4, v4.2
    • Sharding 2020-07-13, Sharding 2020-06-29, Sharding 2020-07-27, Sharding 2020-08-10

    Description

      Syntax:

      { $toHashedIndexKey: <input>}

      Add a new aggregation expression that computes the hash of the input expression using the hash function used to create a hashed index. The expression's evaluate method should pass each element of the input parameter to BSONElementHasher::hash64 with seed DEFAULT_HASH_SEED. If the input expression evaluates to null or missing, still hash this value to mimic MongoDB indexing behavior.

       This will be used as a part of determining new initial split points when resharding a collection.

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          has to be done before

          Task - A task that needs to be done. SERVER-49785 Write and test aggregation pipeline for collection bulk loader for resharding

          • Major - P3 - Major loss of function.
          • Closed
          is depended on by

          Task - A task that needs to be done. SERVER-49525 Sample documents to pick new split points for resharding when new shard key has a hashed field

          • Major - P3 - Major loss of function.
          • Closed
          related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-58047 $toHashedIndexKey expression doesn't add any dependencies

          • Major - P3 - Major loss of function.
          • Closed

          Task - A task that needs to be done. DOCS-15574 [SERVER] Investigate changes in SERVER-69128: Server-side document hashing

          • Major - P3 - Major loss of function.
          • External Review

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-30359 Add a more generalized $hash expression

          • Major - P3 - Major loss of function.
          • Backlog

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-69128 Server-side document hashing

          • Major - P3 - Major loss of function.
          • Closed

          Activity

            People

              kshitij.gupta@mongodb.com Kshitij Gupta
              janna.golden@mongodb.com Janna Golden
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              Dates

                Created:
                Updated:
                Resolved: