spark技术分享CombineUnions Logical Optimization
CombineUnions is a base logical optimization that FIXME.
CombineUnions is part of the Union once-executed batch in the standard batches of the Catalyst Optimizer.
CombineUnions is simply a Catalyst rule for transforming logical plans, i.e. Rule[LogicalPlan].
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// FIXME Demo |
Executing Rule — apply Method
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apply(plan: LogicalPlan): LogicalPlan |
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Note
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apply is part of the Rule Contract to execute (apply) a rule on a TreeNode (e.g. LogicalPlan).
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apply…FIXME
