| // 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.impala.analysis; |
| |
| import static org.apache.impala.analysis.ToSqlOptions.DEFAULT; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.impala.authorization.PrivilegeRequest; |
| import org.apache.impala.catalog.FeView; |
| import org.apache.impala.catalog.View; |
| import org.apache.impala.common.AnalysisException; |
| |
| import com.google.common.base.Joiner; |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * Representation of the WITH clause that may appear before a query statement or insert |
| * statement. A WITH clause contains a list of named view definitions that may be |
| * referenced in the query statement that follows it. |
| * |
| * Scoping rules: |
| * A WITH-clause view is visible inside the query statement that it belongs to. |
| * This includes inline views and nested WITH clauses inside the query statement. |
| * |
| * Each WITH clause establishes a new analysis scope. A WITH-clause view definition |
| * may refer to views from the same WITH-clause appearing to its left, and to all |
| * WITH-clause views from outer scopes. |
| * |
| * References to WITH-clause views are resolved inside out, i.e., a match is found by |
| * first looking in the current scope and then in the enclosing scope(s). |
| * |
| * Views defined within the same WITH-clause may not use the same alias. |
| */ |
| public class WithClause extends StmtNode { |
| ///////////////////////////////////////// |
| // BEGIN: Members that need to be reset() |
| |
| private final List<View> views_; |
| |
| // END: Members that need to be reset() |
| ///////////////////////////////////////// |
| |
| public WithClause(List<View> views) { |
| Preconditions.checkNotNull(views); |
| Preconditions.checkState(!views.isEmpty()); |
| views_ = views; |
| } |
| |
| /** |
| * Analyzes all views and registers them with the analyzer. Enforces scoping rules. |
| * All local views registered with the analyzer are have QueryStmts with resolved |
| * TableRefs to simplify the analysis of view references. |
| */ |
| @Override |
| public void analyze(Analyzer analyzer) throws AnalysisException { |
| // Create a new analyzer for the WITH clause with a new global state (IMPALA-1357) |
| // but a child of 'analyzer' so that the global state for 'analyzer' is not polluted |
| // during analysis of the WITH clause. withClauseAnalyzer is a child of 'analyzer' so |
| // that local views registered in parent blocks are visible here. |
| Analyzer withClauseAnalyzer = Analyzer.createWithNewGlobalState(analyzer); |
| withClauseAnalyzer.setHasWithClause(); |
| if (analyzer.isExplain()) withClauseAnalyzer.setIsExplain(); |
| for (View view: views_) { |
| Analyzer viewAnalyzer = new Analyzer(withClauseAnalyzer); |
| view.getQueryStmt().analyze(viewAnalyzer); |
| // Register this view so that the next view can reference it. |
| withClauseAnalyzer.registerLocalView(view); |
| } |
| // Register all local views with the analyzer. |
| for (FeView localView: withClauseAnalyzer.getLocalViews().values()) { |
| analyzer.registerLocalView(localView); |
| } |
| // Record audit events because the resolved table references won't generate any |
| // when a view is referenced. |
| analyzer.getAccessEvents().addAll(withClauseAnalyzer.getAccessEvents()); |
| |
| // Register all privilege requests made from the root analyzer. |
| for (PrivilegeRequest req: withClauseAnalyzer.getPrivilegeReqs()) { |
| analyzer.registerPrivReq(req); |
| } |
| } |
| |
| /** |
| * C'tor for cloning. |
| */ |
| private WithClause(WithClause other) { |
| Preconditions.checkNotNull(other); |
| views_ = new ArrayList<>(); |
| for (View view: other.views_) { |
| views_.add(new View(view.getName(), view.getQueryStmt().clone(), |
| view.getOriginalColLabels())); |
| } |
| } |
| |
| public void reset() { |
| for (View view: views_) view.getQueryStmt().reset(); |
| } |
| |
| @Override |
| public WithClause clone() { return new WithClause(this); } |
| |
| @Override |
| public final String toSql() { |
| return toSql(DEFAULT); |
| } |
| |
| @Override |
| public String toSql(ToSqlOptions options) { |
| List<String> viewStrings = new ArrayList<>(); |
| for (View view: views_) { |
| // Enclose the view alias and explicit labels in quotes if Hive cannot parse it |
| // without quotes. This is needed for view compatibility between Impala and Hive. |
| String aliasSql = ToSqlUtils.getIdentSql(view.getName()); |
| if (view.getColLabels() != null) { |
| aliasSql += "(" + Joiner.on(", ").join( |
| ToSqlUtils.getIdentSqlList(view.getOriginalColLabels())) + ")"; |
| } |
| viewStrings.add(aliasSql + " AS (" + view.getQueryStmt().toSql(options) + ")"); |
| } |
| return "WITH " + Joiner.on(",").join(viewStrings); |
| } |
| |
| public List<View> getViews() { return views_; } |
| } |