Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/729#discussion_r100681319
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/planner/cost/DrillRelMdSelectivity.java
---
@@ -0,0 +1,219 @@
+/*******************************************************************************
+ * 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.drill.exec.planner.cost;
+
+import org.apache.calcite.plan.RelOptUtil;
+import org.apache.calcite.plan.volcano.RelSubset;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.SingleRel;
+import org.apache.calcite.rel.core.JoinRelType;
+import org.apache.calcite.rel.core.TableScan;
+import org.apache.calcite.rel.metadata.ReflectiveRelMetadataProvider;
+import org.apache.calcite.rel.metadata.RelMdSelectivity;
+import org.apache.calcite.rel.metadata.RelMdUtil;
+import org.apache.calcite.rel.metadata.RelMetadataProvider;
+import org.apache.calcite.rel.metadata.RelMetadataQuery;
+import org.apache.calcite.rel.type.RelDataType;
+import org.apache.calcite.rex.RexBuilder;
+import org.apache.calcite.rex.RexCall;
+import org.apache.calcite.rex.RexInputRef;
+import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.rex.RexUtil;
+import org.apache.calcite.rex.RexVisitor;
+import org.apache.calcite.rex.RexVisitorImpl;
+import org.apache.calcite.sql.SqlKind;
+import org.apache.calcite.util.BuiltInMethod;
+import org.apache.calcite.util.Util;
+import org.apache.drill.exec.planner.common.DrillJoinRelBase;
+import org.apache.drill.exec.planner.common.DrillRelOptUtil;
+import org.apache.drill.exec.planner.logical.DrillTable;
+import org.apache.drill.exec.planner.logical.DrillTranslatableTable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class DrillRelMdSelectivity extends RelMdSelectivity {
+ private static final org.slf4j.Logger logger =
+ org.slf4j.LoggerFactory.getLogger(RelMdSelectivity.class);
+
+ private static final DrillRelMdSelectivity INSTANCE =
+ new DrillRelMdSelectivity();
+
+ public static final RelMetadataProvider SOURCE =
+ ReflectiveRelMetadataProvider.reflectiveSource(
+ BuiltInMethod.SELECTIVITY.method, INSTANCE);
+
+ @Override
+ public Double getSelectivity(RelNode rel, RexNode predicate) {
+ if (rel instanceof TableScan) {
+ return getScanSelectivity((TableScan) rel, predicate);
+ } else if (rel instanceof DrillJoinRelBase) {
+ return getJoinSelectivity(((DrillJoinRelBase) rel), predicate);
+ } else if (rel instanceof SingleRel &&
!DrillRelOptUtil.guessRows(rel)) {
+ return RelMetadataQuery.getSelectivity(((SingleRel)
rel).getInput(), predicate);
+ } else if (rel instanceof RelSubset &&
!DrillRelOptUtil.guessRows(rel)) {
+ if (((RelSubset) rel).getBest() != null) {
+ return RelMetadataQuery.getSelectivity(((RelSubset)rel).getBest(),
predicate);
+ } else if (((RelSubset)rel).getOriginal() != null) {
+ return
RelMetadataQuery.getSelectivity(((RelSubset)rel).getOriginal(), predicate);
+ } else {
+ return super.getSelectivity(rel, predicate);
+ }
+ } else {
+ return super.getSelectivity(rel, predicate);
+ }
+ }
+
+ private Double getJoinSelectivity(DrillJoinRelBase rel, RexNode
predicate) {
+ double sel = 1.0;
+ // determine which filters apply to the left vs right
+ RexNode leftPred = null;
+ RexNode rightPred = null;
+ JoinRelType joinType = rel.getJoinType();
+ final RexBuilder rexBuilder = rel.getCluster().getRexBuilder();
+ int[] adjustments = new int[rel.getRowType().getFieldCount()];
+
+ if (DrillRelOptUtil.guessRows(rel)) {
+ return super.getSelectivity(rel, predicate);
+ }
+
+ if (predicate != null) {
+ RexNode pred;
+ List<RexNode> leftFilters = new ArrayList<RexNode>();
+ List<RexNode> rightFilters = new ArrayList<RexNode>();
+ List<RexNode> joinFilters = new ArrayList<RexNode>();
+ List<RexNode> predList = RelOptUtil.conjunctions(predicate);
+
+ RelOptUtil.classifyFilters(
+ rel,
+ predList,
+ joinType,
+ joinType == JoinRelType.INNER,
+ !joinType.generatesNullsOnLeft(),
+ !joinType.generatesNullsOnRight(),
+ joinFilters,
+ leftFilters,
+ rightFilters);
+ leftPred =
+ RexUtil.composeConjunction(rexBuilder, leftFilters, true);
+ rightPred =
+ RexUtil.composeConjunction(rexBuilder, rightFilters, true);
+ for (RelNode child : rel.getInputs()) {
+ RexNode modifiedPred = null;
+
+ if (child == rel.getLeft()) {
+ pred = leftPred;
+ } else {
+ pred = rightPred;
+ }
+ if (pred != null) {
+ // convert the predicate to reference the types of the children
+ modifiedPred =
+ pred.accept(new RelOptUtil.RexInputConverter(
+ rexBuilder,
+ null,
+ child.getRowType().getFieldList(),
+ adjustments));
+ }
+ sel *= RelMetadataQuery.getSelectivity(child, modifiedPred);
+ }
+ sel *= RelMdUtil.guessSelectivity(
+ RexUtil.composeConjunction(rexBuilder, joinFilters, true));
+ }
+ return sel;
+ }
+
+ private Double getScanSelectivity(TableScan scan, RexNode predicate) {
+ DrillTable table = scan.getTable().unwrap(DrillTable.class);
+ if (table == null) {
+ table =
scan.getTable().unwrap(DrillTranslatableTable.class).getDrillTable();
+ }
+ if (table == null || table.getStatsTable() == null) {
+ return super.getSelectivity(scan, predicate);
+ } else {
+ return getScanSelectivityInternal(table, predicate,
scan.getRowType());
+ }
+ }
+
+ private Double getScanSelectivityInternal(DrillTable table, RexNode
predicate,
+ RelDataType type) {
+ double sel = 1.0;
+
+ if ((predicate == null) || predicate.isAlwaysTrue()) {
+ return sel;
+ }
+
+ for (RexNode pred : RelOptUtil.conjunctions(predicate)) {
+ double orSel = 0;
+ for (RexNode orPred : RelOptUtil.disjunctions(pred)) {
+ //CALCITE guess
+ Double guess = RelMdUtil.guessSelectivity(pred);
+ if (orPred.isA(SqlKind.EQUALS)) {
--- End diff --
This does not seem to use the new information for expressions other than =.
Please see DRILL-5254. Consider feeding the base p(a = value) = 1/NDV into the
calculations described there.
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