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https://issues.apache.org/jira/browse/DRILL-8543?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18091648#comment-18091648
]
ASF GitHub Bot commented on DRILL-8543:
---------------------------------------
rymarm commented on code in PR #3036:
URL: https://github.com/apache/drill/pull/3036#discussion_r3475598961
##########
exec/java-exec/src/main/java/org/apache/drill/exec/planner/logical/MaterializedViewRewriter.java:
##########
@@ -0,0 +1,324 @@
+/*
+ * 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.logical;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.calcite.plan.RelOptMaterialization;
+import org.apache.calcite.plan.RelOptMaterializations;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.RelRoot;
+import org.apache.calcite.schema.SchemaPlus;
+import org.apache.calcite.util.Pair;
+import org.apache.drill.exec.dotdrill.MaterializedView;
+import org.apache.drill.exec.ops.QueryContext;
+import org.apache.drill.exec.planner.sql.conversion.SqlConverter;
+import org.apache.drill.exec.store.AbstractSchema;
+import org.apache.drill.exec.store.StoragePlugin;
+import org.apache.drill.exec.store.StoragePluginRegistry;
+import org.apache.drill.exec.store.StoragePluginRegistry.PluginException;
+import org.apache.drill.exec.store.dfs.FileSystemPlugin;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Utility class for materialized view query rewriting.
+ * <p>
+ * When enabled via planner.enable_materialized_view_rewrite, this class
attempts
+ * to rewrite queries to use materialized views when beneficial.
+ * <p>
+ * Uses Calcite's {@link RelOptMaterializations#useMaterializedViews} API which
+ * normalizes both the query and MV definitions before performing structural
+ * matching via {@link org.apache.calcite.plan.SubstitutionVisitor}.
+ * <p>
+ * Materialized views are discovered by iterating over enabled file-based
+ * storage plugins (the only plugin type that supports MVs) and force-loading
+ * their schemas to find .materialized_view.drill files.
+ */
+public class MaterializedViewRewriter {
+ private static final Logger logger =
LoggerFactory.getLogger(MaterializedViewRewriter.class);
+
+ private final QueryContext context;
+ private final SchemaPlus rootSchema;
+ private final SqlConverter sqlConverter;
+
+ public MaterializedViewRewriter(QueryContext context, SchemaPlus rootSchema,
SqlConverter sqlConverter) {
+ this.context = context;
+ this.rootSchema = rootSchema;
+ this.sqlConverter = sqlConverter;
+ }
+
+ /**
+ * Attempts to rewrite the given RelNode to use a materialized view.
+ *
+ * @param queryRel the query plan to potentially rewrite
+ * @return the rewritten plan using an MV, or the original plan if no
rewrite is possible
+ */
+ public RelNode rewrite(RelNode queryRel) {
+ if (!context.getPlannerSettings().isMaterializedViewRewriteEnabled()) {
+ return queryRel;
+ }
+
+ // Find all available materialized views that have been refreshed
+ List<MaterializedViewCandidate> candidates =
findCandidateMaterializedViews();
+
+ if (candidates.isEmpty()) {
+ logger.debug("No refreshed materialized views available for rewriting");
+ return queryRel;
+ }
+
+ logger.debug("Found {} materialized view candidates for potential
rewriting", candidates.size());
+
+ // Build Calcite RelOptMaterialization objects for each refreshed candidate
+ List<RelOptMaterialization> materializations = new ArrayList<>();
+ for (MaterializedViewCandidate candidate : candidates) {
+ if (!candidate.isRefreshed()) {
+ logger.debug("Skipping MV {} - not refreshed", candidate.getName());
+ continue;
+ }
+
+ try {
+ RelOptMaterialization mat = buildMaterialization(candidate);
+ if (mat != null) {
+ materializations.add(mat);
+ }
+ } catch (Exception e) {
+ logger.debug("Failed to build materialization for MV {}: {}",
candidate.getName(), e.getMessage());
+ }
+ }
+
+ if (materializations.isEmpty()) {
+ logger.debug("No valid materializations could be built");
+ return queryRel;
+ }
+
+ // Use Calcite's materialized view matching API which normalizes both the
+ // query and MV definitions (trimming unused fields, converting
Filter/Project
+ // to Calc, merging, etc.) before performing structural matching.
+ try {
+ List<Pair<RelNode, List<RelOptMaterialization>>> results =
+ RelOptMaterializations.useMaterializedViews(queryRel,
materializations);
+
+ if (!results.isEmpty()) {
+ RelNode rewritten = results.get(0).left;
+ if (logger.isInfoEnabled()) {
+ List<RelOptMaterialization> usedMVs = results.get(0).right;
+ logger.info("Query rewritten to use materialized view(s): {}",
+ !usedMVs.isEmpty() ? usedMVs.get(0).qualifiedTableName :
"unknown");
+ }
+ return rewritten;
+ }
+ } catch (Exception e) {
+ logger.debug("Materialized view rewriting failed: {}", e.getMessage());
+ }
+
+ logger.debug("No materialized view matched the query");
+ return queryRel;
+ }
+
+ /**
+ * Builds a Calcite {@link RelOptMaterialization} for a candidate MV.
+ */
+ private RelOptMaterialization buildMaterialization(MaterializedViewCandidate
candidate) {
+ RelNode mvQueryRel = parseMvSql(candidate);
+ if (mvQueryRel == null) {
+ return null;
+ }
+
+ RelNode mvTableRel = buildMvScanRel(candidate);
+ if (mvTableRel == null) {
+ return null;
+ }
+
+ List<String> qualifiedTableName = java.util.Arrays.asList(
+ candidate.getSchemaPath().split("\\."));
+
+ return new RelOptMaterialization(
+ mvTableRel,
+ mvQueryRel,
+ null,
+ qualifiedTableName
+ );
+ }
+
+ /**
+ * Parses the MV's SQL definition into a RelNode.
+ */
+ private RelNode parseMvSql(MaterializedViewCandidate candidate) {
+ try {
+ String mvSql = candidate.getSql();
+ org.apache.calcite.sql.SqlNode parsedNode = sqlConverter.parse(mvSql);
+ org.apache.calcite.sql.SqlNode validatedNode =
sqlConverter.validate(parsedNode);
+ RelRoot relRoot = sqlConverter.toRel(validatedNode);
+ return relRoot.rel;
+ } catch (Exception e) {
+ logger.debug("Failed to parse MV SQL for {}: {}", candidate.getName(),
e.getMessage());
+ return null;
+ }
+ }
+
+ /**
+ * Builds a RelNode that scans the MV's pre-computed data.
+ */
+ private RelNode buildMvScanRel(MaterializedViewCandidate candidate) {
+ try {
+ String mvDataTable = candidate.getSchemaPath() + ".`" +
candidate.getName() + "_mv_data`";
+
+ // Build explicit column list from the MV's field definitions to avoid
+ // DYNAMIC_STAR type issues with SELECT *
+ List<org.apache.drill.exec.dotdrill.View.Field> fields =
candidate.getMaterializedView().getFields();
+ StringBuilder scanSql = new StringBuilder("SELECT ");
+ if (fields != null && !fields.isEmpty()) {
+ for (int i = 0; i < fields.size(); i++) {
+ if (i > 0) {
+ scanSql.append(", ");
+ }
+ scanSql.append("`").append(fields.get(i).getName()).append("`");
+ }
+ } else {
+ scanSql.append("*");
+ }
+ scanSql.append(" FROM ").append(mvDataTable);
+
+ org.apache.calcite.sql.SqlNode parsedNode =
sqlConverter.parse(scanSql.toString());
+ org.apache.calcite.sql.SqlNode validatedNode =
sqlConverter.validate(parsedNode);
Review Comment:
I probably wasn't accurate. I mean, why did you use a fully qualified class
name `org.apache.calcite.sql.SqlNode` instead of importing it:
```java
import org.apache.calcite.sql.SqlNode ;
```
Just a cosmetic thing :)
> Add Support for Materialized Views
> ----------------------------------
>
> Key: DRILL-8543
> URL: https://issues.apache.org/jira/browse/DRILL-8543
> Project: Apache Drill
> Issue Type: New Feature
> Components: Metadata, Query Planning & Optimization
> Affects Versions: 1.22.0
> Reporter: Charles Givre
> Assignee: Charles Givre
> Priority: Major
> Fix For: 1.23.0
>
>
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