mihaibudiu commented on code in PR #4619:
URL: https://github.com/apache/calcite/pull/4619#discussion_r2590831174
##########
core/src/main/java/org/apache/calcite/rel/rules/SubQueryRemoveRule.java:
##########
@@ -1056,6 +1057,101 @@ private static void matchJoin(SubQueryRemoveRule rule,
RelOptRuleCall call) {
call.transformTo(builder.build());
}
+ private static void matchFilterEnableMarkJoin(SubQueryRemoveRule rule,
RelOptRuleCall call) {
+ final Filter filter = call.rel(0);
+ final Set<CorrelationId> variablesSet = filter.getVariablesSet();
+ final RelBuilder builder = call.builder();
+ builder.push(filter.getInput());
+ List<RexNode> newCondition
+ = rule.applyEnableMarkJoin(variablesSet,
ImmutableList.of(filter.getCondition()), builder);
+ assert newCondition.size() == 1;
+ builder.filter(newCondition.get(0));
+ builder.project(fields(builder, filter.getRowType().getFieldCount()));
+ call.transformTo(builder.build());
+ }
+
+ private static void matchProjectEnableMarkJoin(SubQueryRemoveRule rule,
RelOptRuleCall call) {
+ final Project project = call.rel(0);
+ final Set<CorrelationId> variablesSet = project.getVariablesSet();
+ final RelBuilder builder = call.builder();
+ builder.push(project.getInput());
+ List<RexNode> newProjects
+ = rule.applyEnableMarkJoin(variablesSet, project.getProjects(),
builder);
+ builder.project(newProjects, project.getRowType().getFieldNames());
+ call.transformTo(builder.build());
+ }
+
+ private List<RexNode> applyEnableMarkJoin(Set<CorrelationId>
variablesSetOfRelNode,
+ List<RexNode> expressions, RelBuilder builder) {
+ List<RexNode> newExpressions = new ArrayList<>(expressions);
+ int count = 0;
+ while (true) {
+ final RexSubQuery e = RexUtil.SubQueryFinder.find(newExpressions);
+ if (e == null) {
+ assert count > 0;
+ break;
+ }
+ ++count;
+ final Set<CorrelationId> variablesSet =
RelOptUtil.getVariablesUsed(e.rel);
+ variablesSet.retainAll(variablesSetOfRelNode);
+
+ RexNode target;
+ switch (e.getKind()) {
+ case EXISTS:
+ case IN:
+ case SOME:
+ target =
+ rewriteToMarkJoin(e, variablesSet, builder,
+ builder.peek().getRowType().getFieldCount());
+ break;
+ case SCALAR_QUERY:
+ target =
+ rewriteScalarQuery(e, variablesSet, builder, 1,
+ builder.peek().getRowType().getFieldCount());
+ break;
+ case ARRAY_QUERY_CONSTRUCTOR:
+ case MAP_QUERY_CONSTRUCTOR:
+ case MULTISET_QUERY_CONSTRUCTOR:
+ target =
+ rewriteCollection(e, variablesSet, builder, 1,
+ builder.peek().getRowType().getFieldCount());
+ break;
+ case UNIQUE:
+ target = rewriteUnique(e, builder);
+ break;
+ default:
+ throw new AssertionError(e.getKind());
+ }
+ final RexShuttle shuttle = new ReplaceSubQueryShuttle(e, target);
+ newExpressions = shuttle.apply(newExpressions);
+ }
+ return newExpressions;
+ }
+
+ private static RexNode rewriteToMarkJoin(RexSubQuery e, Set<CorrelationId>
variablesSet,
+ RelBuilder builder, int offset) {
+ builder.push(e.rel);
+
+ final List<RexNode> rightShiftRef = RexUtil.shift(builder.fields(),
offset);
+ final List<RexNode> externalPredicate = new ArrayList<>();
+ final SqlOperator externalOperator;
+ if (e.getKind() == SqlKind.SOME) {
+ SqlQuantifyOperator op = (SqlQuantifyOperator) e.op;
+ externalOperator = RelOptUtil.op(op.comparisonKind,
SqlStdOperatorTable.EQUALS);
+ } else {
+ externalOperator = SqlStdOperatorTable.EQUALS;
Review Comment:
Maybe you want to file an issue to add a SINGLE_JOIN in the future.
(LEFT_SINGLE_JOIN?)
##########
core/src/main/java/org/apache/calcite/sql2rel/TopDownGeneralDecorrelator.java:
##########
@@ -83,6 +83,30 @@
* Improving Unnesting of Complex Queries</a>. It's an improved version of
the paper:
* <a href="https://dl.gi.de/items/137d6917-d8fe-43aa-940b-e27da7c01625";>
* Unnesting Arbitrary Queries</a>.
+ *
+ * <p> Usage notes for TopDownGeneralDecorrelator:
Review Comment:
I think you already have this workflow implemented someplace, maybe in a
test?
Can you just add a `{@link }` to it so people can have a working example?
##########
core/src/main/java/org/apache/calcite/sql2rel/TopDownGeneralDecorrelator.java:
##########
@@ -83,6 +83,30 @@
* Improving Unnesting of Complex Queries</a>. It's an improved version of
the paper:
* <a href="https://dl.gi.de/items/137d6917-d8fe-43aa-940b-e27da7c01625";>
* Unnesting Arbitrary Queries</a>.
+ *
+ * <p> Usage notes for TopDownGeneralDecorrelator:
Review Comment:
This comment will eventually be removed when this becomes THE decorrelator.
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