[GitHub] [calcite] zinking commented on a change in pull request #1991: [CALCITE-3916] Support top-down rule apply and upper bound space pruning

[GitBox <gi...@apache.org>]

zinking commented on a change in pull request #1991:
URL: https://github.com/apache/calcite/pull/1991#discussion_r448349666



##########
File path: core/src/main/java/org/apache/calcite/plan/volcano/IterativeRuleDriver.java
##########
@@ -0,0 +1,87 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.calcite.plan.volcano;
+
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.util.trace.CalciteTrace;
+
+import org.slf4j.Logger;
+
+/***
+ * <p>The algorithm executes repeatedly in a series of phases. In each phase
+ * the exact rules that may be fired varies. The mapping of phases to rule
+ * sets is maintained in the {@link #ruleQueue}.
+ *
+ * <p>In each phase, the planner then iterates over the rule matches presented
+ * by the rule queue until the rule queue becomes empty.
+ */
+class IterativeRuleDriver implements RuleDriver {
+
+  private static final Logger LOGGER = CalciteTrace.getPlannerTracer();
+
+  private final VolcanoPlanner planner;
+  private final VolcanoRuleQueue ruleQueue;
+
+  IterativeRuleDriver(VolcanoPlanner planner) {
+    this.planner = planner;
+    ruleQueue = new VolcanoRuleQueue(planner);
+  }
+
+  @Override public VolcanoRuleQueue getRuleQueue() {
+    return ruleQueue;
+  }
+
+  @Override public void drive() {
+    PLANNING:
+    for (VolcanoPlannerPhase phase : VolcanoPlannerPhase.values()) {
+      while (true) {
+        LOGGER.debug("PLANNER = {}; PHASE = {}; COST = {}",
+            this, phase.toString(), planner.root.bestCost);
+
+        VolcanoRuleMatch match = ruleQueue.popMatch(phase);
+        if (match == null) {
+          break;
+        }
+
+        assert match.getRule().matches(match);
+        try {
+          match.onMatch();
+        } catch (VolcanoTimeoutException e) {
+          planner.canonize();
+          ruleQueue.phaseCompleted(phase);
+          break PLANNING;

Review comment:
       does `call` drive recursively here yield the same semantic ?




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org