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Type: Task
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Resolution: Fixed
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Priority: Major - P3
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Affects Version/s: None
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Component/s: Aggregation Framework
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Fully Compatible
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v4.4, v4.2
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Sharding 2020-07-13, Sharding 2020-06-29, Sharding 2020-07-27, Sharding 2020-08-10
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.
- has to be done before
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SERVER-49785 Write and test aggregation pipeline for collection bulk loader for resharding
- Closed
- is depended on by
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SERVER-49525 Sample documents to pick new split points for resharding when new shard key has a hashed field
- Closed
- is related to
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COMPASS-7601 Add autocomplete support for $toHashedIndexKey
- Closed
- related to
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SERVER-58047 $toHashedIndexKey expression doesn't add any dependencies
- Closed
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SERVER-84462 Consider offering a way for $toHashedIndexKey expression to apply a collation
- Backlog
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SERVER-30359 Add a more generalized $hash expression
- Backlog
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SERVER-69128 Server-side document hashing
- Closed