Xiening Dai created CALCITE-3963:
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             Summary: Maintains logical properties at RelSet (equivalent group) 
instead of RelNode
                 Key: CALCITE-3963
                 URL: https://issues.apache.org/jira/browse/CALCITE-3963
             Project: Calcite
          Issue Type: Bug
            Reporter: Xiening Dai


Currently the logical properties (such as row count, distinct row count, etc) 
are maintained at RelNode level. This creates a number of meta data consistency 
problems, e.g. CALCITE-1048, CALCITE-2166. 

In theory, all RelNodes in a RelSet should share the same logical properties 
per definition of relational equivalence. So it makes more sense to keep 
logical properties at RelSet level, rather than the RelNode. And such 
properties shouldn't change when new sub set is created or subset's best is 
changed.

Specifically I think below build in metadata should fall into the logical 
properties category -

Selectivity

UniqueKeys

ColumnUniqueness

RowCount

MaxRowCount

MinRowCount

DistinctRowCount

Size (averageRowSize, averageColumnSize)

 

 

 

 



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