Module decorrelate

PullUpCorrelatedExpr converts correlated subqueries to Joins

Structs

• PullUpCorrelatedExpr
  This struct rewrite the sub query plan by pull up the correlated expressions(contains outer reference columns) from the inner subquery’s ‘Filter’. It adds the inner reference columns to the ‘Projection’ or ‘Aggregate’ of the subquery if they are missing, so that they can be evaluated by the parent operator as the join condition.

Constants

• UN_MATCHED_ROW_INDICATOR
  Used to indicate the unmatched rows from the inner(subquery) table after the left out Join This is used to handle the Count bug

Type Aliases

• ExprResultMap
  Mapping from expr display name to its evaluation result on empty record batch (for example: ‘count()’ is ‘ScalarValue(0)’, ‘count() + 2’ is ‘ScalarValue(2)’)