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Type: Task
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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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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.
- is related to
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SERVER-94315 Shard filtering bug with collation
- Closed