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From fhueske <...@git.apache.org>
Subject [GitHub] flink pull request #5043: [FLINK-2170] [connectors] Add OrcRowInputFormat an...
Date Wed, 22 Nov 2017 14:19:20 GMT
Github user fhueske commented on a diff in the pull request:

    https://github.com/apache/flink/pull/5043#discussion_r152577385
  
    --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/logical/FlinkLogicalTableSourceScan.scala
---
    @@ -62,7 +62,19 @@ class FlinkLogicalTableSourceScan(
     
       override def computeSelfCost(planner: RelOptPlanner, metadata: RelMetadataQuery): RelOptCost
= {
         val rowCnt = metadata.getRowCount(this)
    -    planner.getCostFactory.makeCost(rowCnt, rowCnt, rowCnt * estimateRowSize(getRowType))
    +
    +    val adjustedCnt: Double = tableSource match {
    +      case f: FilterableTableSource[_] if f.isFilterPushedDown =>
    +        // ensure we prefer FilterableTableSources with pushed-down filters.
    +        rowCnt - 1.0
    --- End diff --
    
    Doesn't really make a difference IMO. It's all about relative costs. We only need to make
sure that a `FilterableTableSource` with pushed down predicates appears to be less expensive
than the same `TableSource` without pushed predicates.
    
    The problem has not occurred before, because the `OrcTableSource` does not guarantee that
all emitted rows match the pushed predicates. Therefore, all predicates are also applied by
a following `Calc` operator such that the cost of that operator is not decreased.


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