Interface SupportsStatisticReport
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- All Known Implementing Classes:
FileSystemTableSource
@PublicEvolving public interface SupportsStatisticReport
Enables to report the estimated statistics provided by theDynamicTableSource
.Statistics are one of the most important inputs to the optimizer cost model, which will generate the most effective execution plan with the lowest cost among all considered candidate plans.
This interface is used to compensate for the missing of statistics in the catalog. The planner will call
reportStatistics()
method when the planner detects the statistics from catalog is unknown. Therefore, the method will be executed as needed.Note: This method is called at plan optimization phase, the implementation of this interface should be as light as possible, but more complete information.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description TableStats
reportStatistics()
Returns the estimated statistics of thisDynamicTableSource
, elseTableStats.UNKNOWN
if some situations are not supported or cannot be handled.
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Method Detail
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reportStatistics
TableStats reportStatistics()
Returns the estimated statistics of thisDynamicTableSource
, elseTableStats.UNKNOWN
if some situations are not supported or cannot be handled.
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