Details
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Type:
Sub-task
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Status: Resolved
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Priority:
Major
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Resolution: Invalid
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Affects Version/s: None
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Fix Version/s: None
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Component/s: None
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Labels:None
Description
This patch introduces CBO step in SemanticAnalyzer. For now the CostBasedOptimizer is an empty shell.
The contract between SemAly and CBO is:
- CBO step is controlled by the 'hive.enable.cbo.flag'.
- When true Hive SemAly will hand CBO a Hive Operator tree (with operators annotated with stats). If it can CBO will return a better plan in Hive AST form.