Details
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Improvement
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Status: Closed
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Minor
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Resolution: Fixed
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None
Description
For the sql
select * from emp tablesample system(20)
`mq.getRowCount(rel)` is null, but we can return `inputRowCount * 0.2`.
Some metadata need to be implemented.
- RelMdAllPredicates
- RelMdColumnOrigins
- RelMdExpressionLineage
- RelMdMaxRowCount
- RelMdMinRowCount
- RelMdPredicates
- RelMdRowCount
Some metadata have been implemented.
- RelMdTableReferences
- RelMdNodeTypes
Some metadabata not need to be implemented.
- RelMdColumnUniqueness (Handle SingleRel)
- RelMdDistribution (Handle SingleRel)
- RelMdDistinctRowCount(Handle RelNode)
- RelMdExplainVisibility(Only TableScan)
- RelMdLowerBoundCost(Handle RelNode)
- RelMdMemory(Handle RelNode)
- RelMdParallelism(Handle RelNode)
- RelMdPercentageOriginalRows(Handle RelNode)
- RelMdPopulationSize(Handle RelNode)
- RelMdSelectivity(Must have predicate)
- RelMdSize(Handle RelNode)
- RelMdUniqueKeys(Handle SingleRel)
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