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Type:
Improvement
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Resolution: Works as Designed
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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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Labels:
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Query Optimization
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QO 2022-06-27, QO 2022-07-11, QO 2022-07-25, QO 2022-08-08, QO 2022-08-22, QO 2022-09-05, QO 2022-09-19, QO 2022-10-03, QE 2022-10-17
Specifically for BSON explain (not for V1 and V2):
- If optimizing under DOP = 1
- Do not add the DistributionRequirement and DistributionAvailability properties to the explain.
- Those default to Centralized in such cases, and are meaningful only for cases where DOP > 1.
For example consider the following printout which displays Centralized distribution.
[j0] ********* Optimized ABT ********* [j0] Properties [cost: 2e-06, localCost: 0, adjustedCE: 0] [j0] | | Logical: [j0] | | cardinalityEstimate: [j0] | | ce: 0 [j0] | | projections: [j0] | | scan_0 [j0] | | collectionAvailability: [j0] | | distributionAvailability: [j0] | | distribution: [j0] | | type: Centralized [j0] | Physical: [j0] | distribution: [j0] | type: Centralized [j0] Root [] [j0] | | projections: [j0] | | scan_0 [j0] | RefBlock: [j0] | Variable [scan_0] [j0] Properties [cost: 2e-06, localCost: 2e-06, adjustedCE: 0] [j0] | | Logical: [j0] | | cardinalityEstimate: [j0] | | ce: 0 [j0] | | projections: [j0] | | scan_0 [j0] | | collectionAvailability: [j0] | | distributionAvailability: [j0] | | distribution: [j0] | | type: Centralized [j0] | Physical: [j0] | projections: [j0] | scan_0 [j0] | distribution: [j0] | type: Centralized [j0] Evaluation [] [j0] | BindBlock: [j0] | [scan_0] [j0] | Const [Nothing] [j0] LimitSkip [] [j0] | limitSkip: [j0] | limit: 0 [j0] | skip: 0 [j0] CoScan [] [j0] ********* Optimized ABT *********