hsyuan commented on a change in pull request #2006:
URL: https://github.com/apache/calcite/pull/2006#discussion_r437062358
##########
File path:
core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableMergeJoin.java
##########
@@ -194,6 +250,81 @@ public static boolean isMergeJoinSupported(JoinRelType
joinType) {
return DeriveMode.BOTH;
}
+ private List<Integer> immutableIntListToList(ImmutableIntList intList, int
offset) {
Review comment:
Can you rebase on master? I just updated this file.
Use `ImmutableIntList.incr` instead.
##########
File path:
core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableMergeJoin.java
##########
@@ -194,6 +250,81 @@ public static boolean isMergeJoinSupported(JoinRelType
joinType) {
return DeriveMode.BOTH;
}
+ private List<Integer> immutableIntListToList(ImmutableIntList intList, int
offset) {
+ ArrayList<Integer> arrayList = new ArrayList<>(intList.size());
+ for (int i : intList) {
+ arrayList.add(i + offset);
+ }
+ return arrayList;
+ }
+
+ private boolean isSubset(List<Integer> a, List<Integer> b) {
+ if (a.size() > b.size()) {
+ return false;
+ }
+ Set<Integer> set = new HashSet<>(b);
+ for (int i = 0; i < a.size(); i++) {
+ if (!set.contains(a.get(i))) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ private boolean isPrefixOrderingNotRequired(List<Integer> a, List<Integer>
b) {
Review comment:
See `RelCollations.containsOrderless`, you can make the private one
public is necessary.
##########
File path:
core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableMergeJoin.java
##########
@@ -101,28 +103,55 @@ public static boolean isMergeJoinSupported(JoinRelType
joinType) {
// Required collation keys can be subset or superset of merge join keys.
RelCollation collation = required.getTrait(RelCollationTraitDef.INSTANCE);
List<Integer> reqKeys = RelCollations.ordinals(collation);
- ImmutableBitSet reqKeySet = ImmutableBitSet.of(reqKeys);
+ // need to copy reqKeys because it is not sortable.
+ reqKeys = new ArrayList<>(reqKeys);
+ List<Integer> leftKeys = immutableIntListToList(joinInfo.leftKeys, 0);
+ List<Integer> rightKeys = immutableIntListToList(joinInfo.rightKeys,
+ left.getRowType().getFieldCount());
+ List<Integer> rightKeysNotShifted =
immutableIntListToList(joinInfo.rightKeys, 0);
+ ImmutableBitSet reqKeySet = ImmutableBitSet.of(reqKeys);
ImmutableBitSet leftKeySet = ImmutableBitSet.of(joinInfo.leftKeys);
ImmutableBitSet rightKeySet = ImmutableBitSet.of(joinInfo.rightKeys)
.shift(left.getRowType().getFieldCount());
Map<Integer, Integer> keyMap = new HashMap<>();
- final int keyCount = leftKeySet.cardinality();
+ final int keyCount = leftKeys.size();
Review comment:
nice catch. in case the keys are `1,1,2,2`. IMHO, we shouldn't see
duplicate join keys in physical merge/hash join operators. They should be
optimized away, because that means the predicate is not pushed down at all.
like foo.a = bar.b and foo.a=bar.c. The predicate bar.b=bar.c should be
pushed down for table bar.
##########
File path:
core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableMergeJoin.java
##########
@@ -101,28 +103,55 @@ public static boolean isMergeJoinSupported(JoinRelType
joinType) {
// Required collation keys can be subset or superset of merge join keys.
RelCollation collation = required.getTrait(RelCollationTraitDef.INSTANCE);
List<Integer> reqKeys = RelCollations.ordinals(collation);
- ImmutableBitSet reqKeySet = ImmutableBitSet.of(reqKeys);
+ // need to copy reqKeys because it is not sortable.
+ reqKeys = new ArrayList<>(reqKeys);
Review comment:
why do you want to sort it?
##########
File path:
core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableMergeJoin.java
##########
@@ -101,28 +103,55 @@ public static boolean isMergeJoinSupported(JoinRelType
joinType) {
// Required collation keys can be subset or superset of merge join keys.
RelCollation collation = required.getTrait(RelCollationTraitDef.INSTANCE);
List<Integer> reqKeys = RelCollations.ordinals(collation);
- ImmutableBitSet reqKeySet = ImmutableBitSet.of(reqKeys);
+ // need to copy reqKeys because it is not sortable.
+ reqKeys = new ArrayList<>(reqKeys);
+ List<Integer> leftKeys = immutableIntListToList(joinInfo.leftKeys, 0);
+ List<Integer> rightKeys = immutableIntListToList(joinInfo.rightKeys,
+ left.getRowType().getFieldCount());
+ List<Integer> rightKeysNotShifted =
immutableIntListToList(joinInfo.rightKeys, 0);
+ ImmutableBitSet reqKeySet = ImmutableBitSet.of(reqKeys);
ImmutableBitSet leftKeySet = ImmutableBitSet.of(joinInfo.leftKeys);
ImmutableBitSet rightKeySet = ImmutableBitSet.of(joinInfo.rightKeys)
.shift(left.getRowType().getFieldCount());
Map<Integer, Integer> keyMap = new HashMap<>();
- final int keyCount = leftKeySet.cardinality();
+ final int keyCount = leftKeys.size();
for (int i = 0; i < keyCount; i++) {
keyMap.put(joinInfo.leftKeys.get(i), joinInfo.rightKeys.get(i));
}
Mappings.TargetMapping mapping = Mappings.target(keyMap,
left.getRowType().getFieldCount(),
right.getRowType().getFieldCount());
- // Only consider exact key match for now
+
if (reqKeySet.equals(leftKeySet)) {
+ // if sort keys equal to left join keys, we can pass through all
collations directly.
RelCollation rightCollation = RexUtil.apply(mapping, collation);
return Pair.of(
required, ImmutableList.of(required,
required.replace(rightCollation)));
+ } else if (isSubset(reqKeys, leftKeys)) {
+ // if sort keys are subset of left join keys, we can extend collations
to make sure all join
+ // keys are sorted.
+ collation = extendCollation(collation, leftKeys);
+ RelCollation rightCollation = RexUtil.apply(mapping, collation);
+ return Pair.of(
+ required, ImmutableList.of(required.replace(collation),
+ required.replace(rightCollation)));
+ } else if (isPrefixOrderingNotRequired(leftKeys, reqKeys)
Review comment:
You can use RelCollations.containsOrderless
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