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Posted to commits@calcite.apache.org by GitBox <gi...@apache.org> on 2020/06/10 00:36:08 UTC
[GitHub] [calcite] amaliujia commented on a change in pull request #2017: [CALCITE-4018] Support trait propagation for EnumerableValues
amaliujia commented on a change in pull request #2017:
URL: https://github.com/apache/calcite/pull/2017#discussion_r437796059
##########
File path: core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableValues.java
##########
@@ -70,6 +74,32 @@ public static EnumerableValues create(RelOptCluster cluster,
return new EnumerableValues(getCluster(), rowType, tuples, traitSet);
}
+ @Override public RelNode passThrough(final RelTraitSet required) {
+ RelCollation collation = required.getCollation();
+ if (collation == null || collation.isDefault()) {
+ return null;
+ }
+ if (tuples.size() > 1) {
+ Ordering<List<RexLiteral>> ordering = null;
+ for (RelFieldCollation fc : collation.getFieldCollations()) {
+ Ordering<List<RexLiteral>> comparator = RelMdCollation.comparator(fc);
+ if (ordering == null) {
+ ordering = comparator;
+ } else {
+ ordering = ordering.compound(comparator);
+ }
+ }
+ if (!ordering.isOrdered(tuples)) {
+ return null;
Review comment:
Could you also explain which this check?
##########
File path: core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableValues.java
##########
@@ -70,6 +74,32 @@ public static EnumerableValues create(RelOptCluster cluster,
return new EnumerableValues(getCluster(), rowType, tuples, traitSet);
}
+ @Override public RelNode passThrough(final RelTraitSet required) {
+ RelCollation collation = required.getCollation();
+ if (collation == null || collation.isDefault()) {
+ return null;
+ }
+ if (tuples.size() > 1) {
+ Ordering<List<RexLiteral>> ordering = null;
+ for (RelFieldCollation fc : collation.getFieldCollations()) {
+ Ordering<List<RexLiteral>> comparator = RelMdCollation.comparator(fc);
+ if (ordering == null) {
+ ordering = comparator;
+ } else {
+ ordering = ordering.compound(comparator);
+ }
Review comment:
Can you add comments to describe what this for loop is doing? Sorry but I had a hard time to understand it.
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