Vladsz83 commented on code in PR #11935:
URL: https://github.com/apache/ignite/pull/11935#discussion_r2007301991
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modules/calcite/src/main/java/org/apache/ignite/internal/processors/query/calcite/prepare/PlannerHelper.java:
##########
@@ -129,6 +152,179 @@ public static IgniteRel optimize(SqlNode sqlNode,
IgnitePlanner planner, IgniteL
}
}
+ /** */
+ private static RelNode actualTopLevelJoinTypeHints(RelNode rel,
List<RelHint> topLevelHints) {
+ assert rel instanceof Hintable;
+
+ List<RelHint> curHints = ((Hintable)rel).getHints();
+
+ List<RelHint> res = new ArrayList<>(topLevelHints.size());
+
+ for (RelHint topHint : topLevelHints) {
+ assert topHint.inheritPath.isEmpty();
+
+ if (!JOIN_TYPE_HINT_NAMES.contains(topHint.hintName))
+ continue;
+
+ if (curHints.isEmpty()) {
+ res.add(topHint);
+
+ continue;
+ }
+
+ for (RelHint curHint : curHints) {
+ // Consider only hints of the join types and which differ by
name or parameters.
+ if (!JOIN_TYPE_HINT_NAMES.contains(curHint.hintName)
+ || topHint.equals(curHint.inheritPath.isEmpty() ? curHint
: curHint.copy(Collections.emptyList())))
+ continue;
+
+ res.add(topHint);
+ }
+ }
+
+ if (!res.isEmpty()) {
+ rel = ((Hintable)rel).withHints(res);
+
+ if (!curHints.isEmpty())
+ rel = ((Hintable)rel).attachHints(curHints);
+ }
+
+ return rel;
+ }
+
+ /**
+ * Tries to optimize joins order.
+ *
+ * @see JoinToMultiJoinRule
+ * @see IgniteMultiJoinOptimizeRule
+ *
+ * @return An node with optimized joins or original {@code root} if didn't
optimize.
+ */
+ private static RelNode optimizeJoinsOrder(IgnitePlanner planner, RelNode
root, List<RelHint> topLevelHints) {
+ List<Join> joins = findNodes(root, Join.class, false);
+
+ // No original joins found, nothing to optimize.
+ if (joins.isEmpty())
+ return root;
+
+ int disabledCnt = 0;
+
+ // If all the joins have the forced order, no need to optimize the
joins order at all.
+ for (Join join : joins) {
+ for (RelHint hint : join.getHints()) {
+ if
(HintDefinition.ENFORCE_JOIN_ORDER.name().equals(hint.hintName)) {
+ ++disabledCnt;
+
+ break;
+ }
+ }
+ }
+
+ if (disabledCnt == joins.size())
+ return root;
+
+ RelNode res = planner.transform(PlannerPhase.HEP_OPTIMIZE_JOIN_ORDER,
root.getTraitSet(), root);
+
+ // Still has a MultiJoin, didn't manage to collect one flat join to
optimize.
+ if (!findNodes(res, MultiJoin.class, true).isEmpty())
+ return root;
+
+ // If a new joins order was proposed, no need to launch another join
order optimizations.
+
planner.setDisabledRules(HintDefinition.ENFORCE_JOIN_ORDER.disabledRules().stream().map(RelOptRule::toString)
+ .collect(Collectors.toList()));
+
+ if (!topLevelHints.isEmpty()) {
+ res = actualTopLevelJoinTypeHints(res, topLevelHints);
+
+ restoreJoinTypeHints(res);
+ }
+
+ return res;
+ }
+
+ /**
+ * A join type hint might be assigned to a query root (top-level hint) or
to a table. Originally, SELECT-level hints
+ * are propagated and assigned to following Joins and TableScans. We lose
assigned to Join nodes ones
+ * in {@link JoinToMultiJoinRule} and have to reassign them from top-level
hints.
+ */
+ private static void restoreJoinTypeHints(RelNode root) {
+ RelShuttle visitor = new RelHomogeneousShuttle() {
+ /** Hints to assign on current tree level. */
+ private final List<List<RelHint>> hintsStack = new ArrayList<>();
+
+ /** Current hint inheritance path. It is important for hint
priority. */
+ private final List<Integer> inputsStack = new ArrayList<>();
+
+ /** {@inheritDoc} */
+ @Override public RelNode visit(RelNode rel) {
+ // Leaf TableScans have no inputs. And we are interrested only
in Joins.
+ if (rel.getInputs().isEmpty())
+ return rel;
+
+ List<RelHint> curHints = Collections.emptyList();
+
+ if ((rel instanceof Hintable) && !(rel instanceof Join) &&
!((Hintable)rel).getHints().isEmpty()) {
Review Comment:
We get joins without hints and repeat hints pushing to join nodes from the
top nodes. If join has a hint, it was already inherited from above. No need to
duplicate. Thus, we assign hints to joins, but do not consider already
assigned. Current join type hint will be pushed further.
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