DRILL-6545: Projection Push down into Lateral Join operator. #1347
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| List<RelDataType> fields = new ArrayList<>(); | ||
| List<String> fieldNames = new ArrayList<>(); | ||
| if (excludeCorrelateColumn) { | ||
| int corrVariable = this.requiredColumns.nextSetBit(0); |
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An assumption here is that there is only 1 correlated column which is true for Drill's Lateral-Unnest implementation but I believe Calcite allows multiple. You could just put a Preconditions check here to be safe.
| public boolean matches(RelOptRuleCall call) { | ||
| Correlate correlate = call.rel(1); | ||
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| if (correlate instanceof DrillLateralJoinRel && ((DrillLateralJoinRel)correlate).excludeCorrelateColumn) { |
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Pls add a comment why this should not match if excludeCorrelateColumn is true.
| @@ -104,6 +118,12 @@ private RelNode rename(RelNode input, List<RelDataTypeField> inputFields, List<S | |||
| return proj; | |||
| } | |||
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| @Override | |||
| public RelWriter explainTerms(RelWriter pw) { | |||
| return super.explainTerms(pw).item("correlate Column: ", this.excludeCorrelateColumn ? this.getColumn() : "None"); | |||
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Will this confuse users in the sense that 'correlate column' is actually always needed for the semantics of lateral join but what excludeCorrelateColumn does is it prevents materialization of that column from the left side of the lateral.
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| private Map<Integer, Integer> buildMapWithoutCorrColumn(RelNode corr, int correlationIndex) { | ||
| int index = 0; | ||
| Map<Integer, Integer> result = new HashedMap(); |
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Any reason for using a HashedMap instead of just HashMap ? (unless you are using the MapIterator it seems the latter should suffice).
| } | ||
| } | ||
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| public static class RexFieldsTransformer { |
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Is this a generic transformer for Rex exprs ? If so, pls add a java doc for future use of this class.
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@amansinha100 Thank you for the review. |
@amansinha100 Please review this PR.
This PR includes.