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Type: Improvement
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Resolution: Unresolved
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Priority: Major - P3
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None
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Affects Version/s: None
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Component/s: None
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Cluster Scalability
Resharding uses SamplingBasedSplitPolicy, which is a descendant of the regular InitialSplitSpolicy base class.
The function calculateHashedSplitPoints defined on the parent is only used in other child classes
(SplitPointsBasedSplitPolicy::SplitPointsBasedSplitPolicy and AbstractTagsBasedSplitPolicy). The SamplingBasedSplitPolicy does not rely on this method based on the code inspection.
If the shard key consists of only a hashed field we do not need to sample and can split the space deterministically among the recipients. This allows us to mitigate known issues with the $sample implementation and allow the final distribution of chunks to mirror the distribution of the customer's data without the downsides of sampling.
- is related to
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SERVER-92762 Set default value of numInitialChunks in reshardCollection to 90
- Closed