com.hazelcast.org.apache.calcite.plan.hep.HepPlanner Maven / Gradle / Ivy
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* 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.
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package com.hazelcast.org.apache.calcite.plan.hep;
import com.hazelcast.org.apache.calcite.linq4j.function.Function2;
import com.hazelcast.org.apache.calcite.linq4j.function.Functions;
import com.hazelcast.org.apache.calcite.plan.AbstractRelOptPlanner;
import com.hazelcast.org.apache.calcite.plan.CommonRelSubExprRule;
import com.hazelcast.org.apache.calcite.plan.Context;
import com.hazelcast.org.apache.calcite.plan.RelDigest;
import com.hazelcast.org.apache.calcite.plan.RelOptCost;
import com.hazelcast.org.apache.calcite.plan.RelOptCostFactory;
import com.hazelcast.org.apache.calcite.plan.RelOptCostImpl;
import com.hazelcast.org.apache.calcite.plan.RelOptMaterialization;
import com.hazelcast.org.apache.calcite.plan.RelOptPlanner;
import com.hazelcast.org.apache.calcite.plan.RelOptRule;
import com.hazelcast.org.apache.calcite.plan.RelOptRuleOperand;
import com.hazelcast.org.apache.calcite.plan.RelTrait;
import com.hazelcast.org.apache.calcite.plan.RelTraitSet;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.convert.Converter;
import com.hazelcast.org.apache.calcite.rel.convert.ConverterRule;
import com.hazelcast.org.apache.calcite.rel.convert.TraitMatchingRule;
import com.hazelcast.org.apache.calcite.rel.core.RelFactories;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMdUtil;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMetadataProvider;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMetadataQuery;
import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.org.apache.calcite.util.Pair;
import com.hazelcast.org.apache.calcite.util.Util;
import com.hazelcast.org.apache.calcite.util.graph.BreadthFirstIterator;
import com.hazelcast.org.apache.calcite.util.graph.CycleDetector;
import com.hazelcast.org.apache.calcite.util.graph.DefaultDirectedGraph;
import com.hazelcast.org.apache.calcite.util.graph.DefaultEdge;
import com.hazelcast.org.apache.calcite.util.graph.DepthFirstIterator;
import com.hazelcast.org.apache.calcite.util.graph.DirectedGraph;
import com.hazelcast.org.apache.calcite.util.graph.Graphs;
import com.hazelcast.org.apache.calcite.util.graph.TopologicalOrderIterator;
import com.hazelcast.com.google.common.collect.ImmutableList;
import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import static com.hazelcast.com.google.common.base.Preconditions.checkArgument;
import static com.hazelcast.org.apache.calcite.linq4j.Nullness.castNonNull;
import static java.util.Objects.requireNonNull;
/**
* HepPlanner is a heuristic implementation of the {@link RelOptPlanner}
* interface.
*/
public class HepPlanner extends AbstractRelOptPlanner {
//~ Instance fields --------------------------------------------------------
private final HepProgram mainProgram;
private @Nullable HepRelVertex root;
private @Nullable RelTraitSet requestedRootTraits;
/**
* {@link RelDataType} is represented with its field types as {@code List}.
* This enables to treat as equal projects that differ in expression names only.
*/
private final Map mapDigestToVertex =
new HashMap<>();
private int nTransformations;
private int graphSizeLastGC;
private int nTransformationsLastGC;
private final boolean noDag;
/**
* Query graph, with edges directed from parent to child. This is a
* single-rooted DAG, possibly with additional roots corresponding to
* discarded plan fragments which remain to be garbage-collected.
*/
private final DirectedGraph graph =
DefaultDirectedGraph.create();
private final Function2 onCopyHook;
private final List materializations =
new ArrayList<>();
//~ Constructors -----------------------------------------------------------
/**
* Creates a new HepPlanner that allows DAG.
*
* @param program program controlling rule application
*/
public HepPlanner(HepProgram program) {
this(program, null, false, null, RelOptCostImpl.FACTORY);
}
/**
* Creates a new HepPlanner that allows DAG.
*
* @param program program controlling rule application
* @param context to carry while planning
*/
public HepPlanner(HepProgram program, @Nullable Context context) {
this(program, context, false, null, RelOptCostImpl.FACTORY);
}
/**
* Creates a new HepPlanner with the option to keep the graph a
* tree (noDag = true) or allow DAG (noDag = false).
*
* @param noDag If false, create shared nodes if expressions are
* identical
* @param program Program controlling rule application
* @param onCopyHook Function to call when a node is copied
*/
public HepPlanner(
HepProgram program,
@Nullable Context context,
boolean noDag,
@Nullable Function2 onCopyHook,
RelOptCostFactory costFactory) {
super(costFactory, context);
this.mainProgram = requireNonNull(program, "program");
this.onCopyHook = Util.first(onCopyHook, Functions.ignore2());
this.noDag = noDag;
}
//~ Methods ----------------------------------------------------------------
@Override public void setRoot(RelNode rel) {
root = addRelToGraph(rel);
dumpGraph();
}
@Override public @Nullable RelNode getRoot() {
return root;
}
@Override public void clear() {
super.clear();
for (RelOptRule rule : getRules()) {
removeRule(rule);
}
this.materializations.clear();
}
@Override public RelNode changeTraits(RelNode rel, RelTraitSet toTraits) {
// Ignore traits, except for the root, where we remember
// what the final conversion should be.
if ((rel == root) || (rel == requireNonNull(root, "root").getCurrentRel())) {
requestedRootTraits = toTraits;
}
return rel;
}
@Override public RelNode findBestExp() {
requireNonNull(root, "root");
executeProgram(mainProgram);
// Get rid of everything except what's in the final plan.
collectGarbage();
dumpRuleAttemptsInfo();
return buildFinalPlan(requireNonNull(root, "root"));
}
/** Top-level entry point for a program. Initializes state and then invokes
* the program. */
private void executeProgram(HepProgram program) {
final HepInstruction.PrepareContext px =
HepInstruction.PrepareContext.create(this);
final HepState state = program.prepare(px);
state.execute();
}
void executeProgram(HepProgram instruction, HepProgram.State state) {
state.init();
state.instructionStates.forEach(instructionState -> {
instructionState.execute();
int delta = nTransformations - nTransformationsLastGC;
if (delta > graphSizeLastGC) {
// The number of transformations performed since the last
// garbage collection is greater than the number of vertices in
// the graph at that time. That means there should be a
// reasonable amount of garbage to collect now. We do it this
// way to amortize garbage collection cost over multiple
// instructions, while keeping the highwater memory usage
// proportional to the graph size.
collectGarbage();
}
});
}
void executeMatchLimit(HepInstruction.MatchLimit instruction,
HepInstruction.MatchLimit.State state) {
LOGGER.trace("Setting match limit to {}", instruction.limit);
state.programState.matchLimit = instruction.limit;
}
void executeMatchOrder(HepInstruction.MatchOrder instruction,
HepInstruction.MatchOrder.State state) {
LOGGER.trace("Setting match order to {}", instruction.order);
state.programState.matchOrder = instruction.order;
}
void executeRuleInstance(HepInstruction.RuleInstance instruction,
HepInstruction.RuleInstance.State state) {
if (state.programState.skippingGroup()) {
return;
}
applyRules(state.programState, ImmutableList.of(instruction.rule), true);
}
void executeRuleLookup(HepInstruction.RuleLookup instruction,
HepInstruction.RuleLookup.State state) {
if (state.programState.skippingGroup()) {
return;
}
RelOptRule rule = state.rule;
if (rule == null) {
state.rule = rule = getRuleByDescription(instruction.ruleDescription);
LOGGER.trace("Looking up rule with description {}, found {}",
instruction.ruleDescription, rule);
}
if (rule != null) {
applyRules(state.programState, ImmutableList.of(rule), true);
}
}
void executeRuleClass(HepInstruction.RuleClass instruction,
HepInstruction.RuleClass.State state) {
if (state.programState.skippingGroup()) {
return;
}
LOGGER.trace("Applying rule class {}", instruction.ruleClass);
Set ruleSet = state.ruleSet;
if (ruleSet == null) {
state.ruleSet = ruleSet = new LinkedHashSet<>();
Class ruleClass = instruction.ruleClass;
for (RelOptRule rule : mapDescToRule.values()) {
if (ruleClass.isInstance(rule)) {
ruleSet.add(rule);
}
}
}
applyRules(state.programState, ruleSet, true);
}
void executeRuleCollection(HepInstruction.RuleCollection instruction,
HepInstruction.RuleCollection.State state) {
if (state.programState.skippingGroup()) {
return;
}
applyRules(state.programState, instruction.rules, true);
}
void executeConverterRules(HepInstruction.ConverterRules instruction,
HepInstruction.ConverterRules.State state) {
checkArgument(state.programState.group == null);
Set ruleSet = state.ruleSet;
if (ruleSet == null) {
state.ruleSet = ruleSet = new LinkedHashSet<>();
for (RelOptRule rule : mapDescToRule.values()) {
if (!(rule instanceof ConverterRule)) {
continue;
}
ConverterRule converter = (ConverterRule) rule;
if (converter.isGuaranteed() != instruction.guaranteed) {
continue;
}
// Add the rule itself to work top-down
ruleSet.add(converter);
if (!instruction.guaranteed) {
// Add a TraitMatchingRule to work bottom-up
ruleSet.add(
TraitMatchingRule.config(converter, RelFactories.LOGICAL_BUILDER)
.toRule());
}
}
}
applyRules(state.programState, ruleSet, instruction.guaranteed);
}
void executeCommonRelSubExprRules(
HepInstruction.CommonRelSubExprRules instruction,
HepInstruction.CommonRelSubExprRules.State state) {
checkArgument(state.programState.group == null);
Set ruleSet = state.ruleSet;
if (ruleSet == null) {
state.ruleSet = ruleSet = new LinkedHashSet<>();
for (RelOptRule rule : mapDescToRule.values()) {
if (!(rule instanceof CommonRelSubExprRule)) {
continue;
}
ruleSet.add(rule);
}
}
applyRules(state.programState, ruleSet, true);
}
void executeSubProgram(HepInstruction.SubProgram instruction,
HepInstruction.SubProgram.State state) {
LOGGER.trace("Entering subprogram");
for (;;) {
int nTransformationsBefore = nTransformations;
state.programState.execute();
if (nTransformations == nTransformationsBefore) {
// Nothing happened this time around.
break;
}
}
LOGGER.trace("Leaving subprogram");
}
void executeBeginGroup(HepInstruction.BeginGroup instruction,
HepInstruction.BeginGroup.State state) {
checkArgument(state.programState.group == null);
state.programState.group = state.endGroup;
LOGGER.trace("Entering group");
}
void executeEndGroup(HepInstruction.EndGroup instruction,
HepInstruction.EndGroup.State state) {
checkArgument(state.programState.group == state);
state.programState.group = null;
state.collecting = false;
applyRules(state.programState, state.ruleSet, true);
LOGGER.trace("Leaving group");
}
private int depthFirstApply(HepProgram.State programState,
Iterator iter, Collection rules,
boolean forceConversions, int nMatches) {
while (iter.hasNext()) {
HepRelVertex vertex = iter.next();
for (RelOptRule rule : rules) {
HepRelVertex newVertex =
applyRule(rule, vertex, forceConversions);
if (newVertex == null || newVertex == vertex) {
continue;
}
++nMatches;
if (nMatches >= programState.matchLimit) {
return nMatches;
}
// To the extent possible, pick up where we left
// off; have to create a new iterator because old
// one was invalidated by transformation.
Iterator depthIter =
getGraphIterator(programState, newVertex);
nMatches =
depthFirstApply(programState, depthIter, rules, forceConversions,
nMatches);
break;
}
}
return nMatches;
}
private void applyRules(HepProgram.State programState,
Collection rules, boolean forceConversions) {
final HepInstruction.EndGroup.State group = programState.group;
if (group != null) {
checkArgument(group.collecting);
Set ruleSet = requireNonNull(group.ruleSet, "group.ruleSet");
ruleSet.addAll(rules);
return;
}
LOGGER.trace("Applying rule set {}", rules);
final boolean fullRestartAfterTransformation =
programState.matchOrder != HepMatchOrder.ARBITRARY
&& programState.matchOrder != HepMatchOrder.DEPTH_FIRST;
int nMatches = 0;
boolean fixedPoint;
do {
Iterator iter =
getGraphIterator(programState, requireNonNull(root, "root"));
fixedPoint = true;
while (iter.hasNext()) {
HepRelVertex vertex = iter.next();
for (RelOptRule rule : rules) {
HepRelVertex newVertex =
applyRule(rule, vertex, forceConversions);
if (newVertex == null || newVertex == vertex) {
continue;
}
++nMatches;
if (nMatches >= programState.matchLimit) {
return;
}
if (fullRestartAfterTransformation) {
iter = getGraphIterator(programState, requireNonNull(root, "root"));
} else {
// To the extent possible, pick up where we left
// off; have to create a new iterator because old
// one was invalidated by transformation.
iter = getGraphIterator(programState, newVertex);
if (programState.matchOrder == HepMatchOrder.DEPTH_FIRST) {
nMatches =
depthFirstApply(programState, iter, rules, forceConversions, nMatches);
if (nMatches >= programState.matchLimit) {
return;
}
}
// Remember to go around again since we're
// skipping some stuff.
fixedPoint = false;
}
break;
}
}
} while (!fixedPoint);
}
private Iterator getGraphIterator(
HepProgram.State programState, HepRelVertex start) {
// Make sure there's no garbage, because topological sort
// doesn't start from a specific root, and rules can't
// deal with firing on garbage.
// FIXME jvs 25-Sept-2006: I had to move this earlier because
// of FRG-215, which is still under investigation. Once we
// figure that one out, move down to location below for
// better optimizer performance.
collectGarbage();
switch (requireNonNull(programState.matchOrder, "programState.matchOrder")) {
case ARBITRARY:
case DEPTH_FIRST:
return DepthFirstIterator.of(graph, start).iterator();
case TOP_DOWN:
assert start == root;
// see above
/*
collectGarbage();
*/
return TopologicalOrderIterator.of(graph).iterator();
case BOTTOM_UP:
default:
assert start == root;
// see above
/*
collectGarbage();
*/
// TODO jvs 4-Apr-2006: enhance TopologicalOrderIterator
// to support reverse walk.
final List list = new ArrayList<>();
for (HepRelVertex vertex : TopologicalOrderIterator.of(graph)) {
list.add(vertex);
}
Collections.reverse(list);
return list.iterator();
}
}
private @Nullable HepRelVertex applyRule(
RelOptRule rule,
HepRelVertex vertex,
boolean forceConversions) {
if (!graph.vertexSet().contains(vertex)) {
return null;
}
RelTrait parentTrait = null;
List parents = null;
if (rule instanceof ConverterRule) {
// Guaranteed converter rules require special casing to make sure
// they only fire where actually needed, otherwise they tend to
// fire to infinity and beyond.
ConverterRule converterRule = (ConverterRule) rule;
if (converterRule.isGuaranteed() || !forceConversions) {
if (!doesConverterApply(converterRule, vertex)) {
return null;
}
parentTrait = converterRule.getOutTrait();
}
} else if (rule instanceof CommonRelSubExprRule) {
// Only fire CommonRelSubExprRules if the vertex is a common
// subexpression.
List parentVertices = getVertexParents(vertex);
if (parentVertices.size() < 2) {
return null;
}
parents = new ArrayList<>();
for (HepRelVertex pVertex : parentVertices) {
parents.add(pVertex.getCurrentRel());
}
}
final List bindings = new ArrayList<>();
final Map> nodeChildren = new HashMap<>();
boolean match =
matchOperands(
rule.getOperand(),
vertex.getCurrentRel(),
bindings,
nodeChildren);
if (!match) {
return null;
}
HepRuleCall call =
new HepRuleCall(
this,
rule.getOperand(),
bindings.toArray(new RelNode[0]),
nodeChildren,
parents);
// Allow the rule to apply its own side-conditions.
if (!rule.matches(call)) {
return null;
}
fireRule(call);
if (!call.getResults().isEmpty()) {
return applyTransformationResults(
vertex,
call,
parentTrait);
}
return null;
}
private boolean doesConverterApply(
ConverterRule converterRule,
HepRelVertex vertex) {
RelTrait outTrait = converterRule.getOutTrait();
List parents = Graphs.predecessorListOf(graph, vertex);
for (HepRelVertex parent : parents) {
RelNode parentRel = parent.getCurrentRel();
if (parentRel instanceof Converter) {
// We don't support converter chains.
continue;
}
if (parentRel.getTraitSet().contains(outTrait)) {
// This parent wants the traits produced by the converter.
return true;
}
}
return (vertex == root)
&& (requestedRootTraits != null)
&& requestedRootTraits.contains(outTrait);
}
/**
* Retrieves the parent vertices of a vertex. If a vertex appears multiple
* times as an input into a parent, then that counts as multiple parents,
* one per input reference.
*
* @param vertex the vertex
* @return the list of parents for the vertex
*/
private List getVertexParents(HepRelVertex vertex) {
final List parents = new ArrayList<>();
final List parentVertices =
Graphs.predecessorListOf(graph, vertex);
for (HepRelVertex pVertex : parentVertices) {
RelNode parent = pVertex.getCurrentRel();
for (int i = 0; i < parent.getInputs().size(); i++) {
HepRelVertex child = (HepRelVertex) parent.getInputs().get(i);
if (child == vertex) {
parents.add(pVertex);
}
}
}
return parents;
}
private static boolean matchOperands(
RelOptRuleOperand operand,
RelNode rel,
List bindings,
Map> nodeChildren) {
if (!operand.matches(rel)) {
return false;
}
for (RelNode input : rel.getInputs()) {
if (!(input instanceof HepRelVertex)) {
// The graph could be partially optimized for materialized view. In that
// case, the input would be a RelNode and shouldn't be matched again here.
return false;
}
}
bindings.add(rel);
@SuppressWarnings("unchecked")
List childRels = (List) rel.getInputs();
switch (operand.childPolicy) {
case ANY:
return true;
case UNORDERED:
// For each operand, at least one child must match. If
// matchAnyChildren, usually there's just one operand.
for (RelOptRuleOperand childOperand : operand.getChildOperands()) {
boolean match = false;
for (HepRelVertex childRel : childRels) {
match =
matchOperands(
childOperand,
childRel.getCurrentRel(),
bindings,
nodeChildren);
if (match) {
break;
}
}
if (!match) {
return false;
}
}
final List children = new ArrayList<>(childRels.size());
for (HepRelVertex childRel : childRels) {
children.add(childRel.getCurrentRel());
}
nodeChildren.put(rel, children);
return true;
default:
int n = operand.getChildOperands().size();
if (childRels.size() < n) {
return false;
}
for (Pair pair
: Pair.zip(childRels, operand.getChildOperands())) {
boolean match =
matchOperands(
pair.right,
pair.left.getCurrentRel(),
bindings,
nodeChildren);
if (!match) {
return false;
}
}
return true;
}
}
private HepRelVertex applyTransformationResults(
HepRelVertex vertex,
HepRuleCall call,
@Nullable RelTrait parentTrait) {
// TODO jvs 5-Apr-2006: Take the one that gives the best
// global cost rather than the best local cost. That requires
// "tentative" graph edits.
assert !call.getResults().isEmpty();
RelNode bestRel = null;
if (call.getResults().size() == 1) {
// No costing required; skip it to minimize the chance of hitting
// rels without cost information.
bestRel = call.getResults().get(0);
} else {
RelOptCost bestCost = null;
final RelMetadataQuery mq = call.getMetadataQuery();
for (RelNode rel : call.getResults()) {
RelOptCost thisCost = getCost(rel, mq);
if (LOGGER.isTraceEnabled()) {
// Keep in the isTraceEnabled for the getRowCount method call
LOGGER.trace("considering {} with cumulative cost={} and rowcount={}",
rel, thisCost, mq.getRowCount(rel));
}
if (thisCost == null) {
continue;
}
if (bestRel == null || thisCost.isLt(castNonNull(bestCost))) {
bestRel = rel;
bestCost = thisCost;
}
}
}
++nTransformations;
notifyTransformation(
call,
requireNonNull(bestRel, "bestRel"),
true);
// Before we add the result, make a copy of the list of vertex's
// parents. We'll need this later during contraction so that
// we only update the existing parents, not the new parents
// (otherwise loops can result). Also take care of filtering
// out parents by traits in case we're dealing with a converter rule.
final List allParents =
Graphs.predecessorListOf(graph, vertex);
final List parents = new ArrayList<>();
for (HepRelVertex parent : allParents) {
if (parentTrait != null) {
RelNode parentRel = parent.getCurrentRel();
if (parentRel instanceof Converter) {
// We don't support automatically chaining conversions.
// Treating a converter as a candidate parent here
// can cause the "iParentMatch" check below to
// throw away a new converter needed in
// the multi-parent DAG case.
continue;
}
if (!parentRel.getTraitSet().contains(parentTrait)) {
// This parent does not want the converted result.
continue;
}
}
parents.add(parent);
}
HepRelVertex newVertex = addRelToGraph(bestRel);
// There's a chance that newVertex is the same as one
// of the parents due to common subexpression recognition
// (e.g. the LogicalProject added by JoinCommuteRule). In that
// case, treat the transformation as a nop to avoid
// creating a loop.
int iParentMatch = parents.indexOf(newVertex);
if (iParentMatch != -1) {
newVertex = parents.get(iParentMatch);
} else {
contractVertices(newVertex, vertex, parents);
}
if (getListener() != null) {
// Assume listener doesn't want to see garbage.
collectGarbage();
}
notifyTransformation(
call,
bestRel,
false);
dumpGraph();
return newVertex;
}
@Override public RelNode register(
RelNode rel,
@Nullable RelNode equivRel) {
// Ignore; this call is mostly to tell Volcano how to avoid
// infinite loops.
return rel;
}
@Override public void onCopy(RelNode rel, RelNode newRel) {
onCopyHook.apply(rel, newRel);
}
@Override public RelNode ensureRegistered(RelNode rel, @Nullable RelNode equivRel) {
return rel;
}
@Override public boolean isRegistered(RelNode rel) {
return true;
}
private HepRelVertex addRelToGraph(
RelNode rel) {
// Check if a transformation already produced a reference
// to an existing vertex.
if (graph.vertexSet().contains(rel)) {
return (HepRelVertex) rel;
}
// Recursively add children, replacing this rel's inputs
// with corresponding child vertices.
final List inputs = rel.getInputs();
final List newInputs = new ArrayList<>();
for (RelNode input1 : inputs) {
HepRelVertex childVertex = addRelToGraph(input1);
newInputs.add(childVertex);
}
if (!Util.equalShallow(inputs, newInputs)) {
RelNode oldRel = rel;
rel = rel.copy(rel.getTraitSet(), newInputs);
onCopy(oldRel, rel);
}
// Compute digest first time we add to DAG,
// otherwise can't get equivVertex for common sub-expression
rel.recomputeDigest();
// try to find equivalent rel only if DAG is allowed
if (!noDag) {
// Now, check if an equivalent vertex already exists in graph.
HepRelVertex equivVertex = mapDigestToVertex.get(rel.getRelDigest());
if (equivVertex != null) {
// Use existing vertex.
return equivVertex;
}
}
// No equivalence: create a new vertex to represent this rel.
HepRelVertex newVertex = new HepRelVertex(rel);
graph.addVertex(newVertex);
updateVertex(newVertex, rel);
for (RelNode input : rel.getInputs()) {
graph.addEdge(newVertex, (HepRelVertex) input);
}
nTransformations++;
return newVertex;
}
private void contractVertices(
HepRelVertex preservedVertex,
HepRelVertex discardedVertex,
List parents) {
if (preservedVertex == discardedVertex) {
// Nop.
return;
}
RelNode rel = preservedVertex.getCurrentRel();
updateVertex(preservedVertex, rel);
// Update specified parents of discardedVertex.
for (HepRelVertex parent : parents) {
RelNode parentRel = parent.getCurrentRel();
List inputs = parentRel.getInputs();
for (int i = 0; i < inputs.size(); ++i) {
RelNode child = inputs.get(i);
if (child != discardedVertex) {
continue;
}
parentRel.replaceInput(i, preservedVertex);
}
clearCache(parent);
graph.removeEdge(parent, discardedVertex);
graph.addEdge(parent, preservedVertex);
updateVertex(parent, parentRel);
}
// NOTE: we don't actually do graph.removeVertex(discardedVertex),
// because it might still be reachable from preservedVertex.
// Leave that job for garbage collection.
if (discardedVertex == root) {
root = preservedVertex;
}
}
/**
* Clears metadata cache for the RelNode and its ancestors.
*
* @param vertex relnode
*/
private void clearCache(HepRelVertex vertex) {
RelMdUtil.clearCache(vertex.getCurrentRel());
if (!RelMdUtil.clearCache(vertex)) {
return;
}
Queue queue =
new ArrayDeque<>(graph.getInwardEdges(vertex));
while (!queue.isEmpty()) {
DefaultEdge edge = queue.remove();
HepRelVertex source = (HepRelVertex) edge.source;
RelMdUtil.clearCache(source.getCurrentRel());
if (RelMdUtil.clearCache(source)) {
queue.addAll(graph.getInwardEdges(source));
}
}
}
private void updateVertex(HepRelVertex vertex, RelNode rel) {
if (rel != vertex.getCurrentRel()) {
// REVIEW jvs 5-Apr-2006: We'll do this again later
// during garbage collection. Or we could get rid
// of mark/sweep garbage collection and do it precisely
// at this point by walking down to all rels which are only
// reachable from here.
notifyDiscard(vertex.getCurrentRel());
}
RelDigest oldKey = vertex.getCurrentRel().getRelDigest();
if (mapDigestToVertex.get(oldKey) == vertex) {
mapDigestToVertex.remove(oldKey);
}
// When a transformation happened in one rule apply, support
// vertex2 replace vertex1, but the current relNode of
// vertex1 and vertex2 is same,
// then the digest is also same. but we can't remove vertex2,
// otherwise the digest will be removed wrongly in the mapDigestToVertex
// when collectGC
// so it must update the digest that map to vertex
mapDigestToVertex.put(rel.getRelDigest(), vertex);
if (rel != vertex.getCurrentRel()) {
vertex.replaceRel(rel);
}
notifyEquivalence(
rel,
vertex,
false);
}
private RelNode buildFinalPlan(HepRelVertex vertex) {
RelNode rel = vertex.getCurrentRel();
notifyChosen(rel);
// Recursively process children, replacing this rel's inputs
// with corresponding child rels.
List inputs = rel.getInputs();
for (int i = 0; i < inputs.size(); ++i) {
RelNode child = inputs.get(i);
if (!(child instanceof HepRelVertex)) {
// Already replaced.
continue;
}
child = buildFinalPlan((HepRelVertex) child);
rel.replaceInput(i, child);
}
RelMdUtil.clearCache(rel);
rel.recomputeDigest();
return rel;
}
private void collectGarbage() {
if (nTransformations == nTransformationsLastGC) {
// No modifications have taken place since the last gc,
// so there can't be any garbage.
return;
}
nTransformationsLastGC = nTransformations;
LOGGER.trace("collecting garbage");
// Yer basic mark-and-sweep.
final Set rootSet = new HashSet<>();
HepRelVertex root = requireNonNull(this.root, "this.root");
if (graph.vertexSet().contains(root)) {
BreadthFirstIterator.reachable(rootSet, graph, root);
}
if (rootSet.size() == graph.vertexSet().size()) {
// Everything is reachable: no garbage to collect.
return;
}
final Set sweepSet = new HashSet<>();
for (HepRelVertex vertex : graph.vertexSet()) {
if (!rootSet.contains(vertex)) {
sweepSet.add(vertex);
RelNode rel = vertex.getCurrentRel();
notifyDiscard(rel);
}
}
assert !sweepSet.isEmpty();
graph.removeAllVertices(sweepSet);
graphSizeLastGC = graph.vertexSet().size();
// Clean up digest map too.
Iterator> digestIter =
mapDigestToVertex.entrySet().iterator();
while (digestIter.hasNext()) {
HepRelVertex vertex = digestIter.next().getValue();
if (sweepSet.contains(vertex)) {
digestIter.remove();
}
}
}
private void assertNoCycles() {
// Verify that the graph is acyclic.
final CycleDetector cycleDetector =
new CycleDetector<>(graph);
Set cyclicVertices = cycleDetector.findCycles();
if (cyclicVertices.isEmpty()) {
return;
}
throw new AssertionError("Query graph cycle detected in HepPlanner: "
+ cyclicVertices);
}
private void dumpGraph() {
if (!LOGGER.isTraceEnabled()) {
return;
}
assertNoCycles();
HepRelVertex root = this.root;
if (root == null) {
LOGGER.trace("dumpGraph: root is null");
return;
}
final RelMetadataQuery mq = root.getCluster().getMetadataQuery();
final StringBuilder sb = new StringBuilder();
sb.append("\nBreadth-first from root: {\n");
for (HepRelVertex vertex : BreadthFirstIterator.of(graph, root)) {
sb.append(" ")
.append(vertex)
.append(" = ");
RelNode rel = vertex.getCurrentRel();
sb.append(rel)
.append(", rowcount=")
.append(mq.getRowCount(rel))
.append(", cumulative cost=")
.append(getCost(rel, mq))
.append('\n');
}
sb.append("}");
LOGGER.trace(sb.toString());
}
@Deprecated // to be removed before 2.0
@Override public void registerMetadataProviders(List list) {
list.add(0, new HepRelMetadataProvider());
}
@Deprecated // to be removed before 2.0
@Override public long getRelMetadataTimestamp(RelNode rel) {
// TODO jvs 20-Apr-2006: This is overly conservative. Better would be
// to keep a timestamp per HepRelVertex, and update only affected
// vertices and all ancestors on each transformation.
return nTransformations;
}
@Override public ImmutableList getMaterializations() {
return ImmutableList.copyOf(materializations);
}
@Override public void addMaterialization(RelOptMaterialization materialization) {
materializations.add(materialization);
}
}
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