/*
* Licensed 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 com.facebook.presto.sql.rewrite;
import com.facebook.presto.Session;
import com.facebook.presto.metadata.Metadata;
import com.facebook.presto.security.AccessControl;
import com.facebook.presto.sql.analyzer.QueryExplainer;
import com.facebook.presto.sql.analyzer.SemanticException;
import com.facebook.presto.sql.parser.SqlParser;
import com.facebook.presto.sql.tree.AstVisitor;
import com.facebook.presto.sql.tree.Execute;
import com.facebook.presto.sql.tree.Explain;
import com.facebook.presto.sql.tree.ExplainFormat;
import com.facebook.presto.sql.tree.ExplainOption;
import com.facebook.presto.sql.tree.ExplainType;
import com.facebook.presto.sql.tree.Expression;
import com.facebook.presto.sql.tree.Node;
import com.facebook.presto.sql.tree.Statement;
import java.util.List;
import java.util.Optional;
import static com.facebook.presto.execution.SqlQueryManager.unwrapExecuteStatement;
import static com.facebook.presto.execution.SqlQueryManager.validateParameters;
import static com.facebook.presto.sql.QueryUtil.singleValueQuery;
import static com.facebook.presto.sql.tree.ExplainFormat.Type.TEXT;
import static com.facebook.presto.sql.tree.ExplainType.Type.LOGICAL;
import static com.facebook.presto.sql.tree.ExplainType.Type.VALIDATE;
import static java.util.Collections.emptyList;
import static java.util.Objects.requireNonNull;
final class ExplainRewrite
implements StatementRewrite.Rewrite
{
@Override
public Statement rewrite(
Session session,
Metadata metadata,
SqlParser parser,
Optional<QueryExplainer> queryExplainer,
Statement node,
List<Expression> parameters,
AccessControl accessControl)
{
return (Statement) new Visitor(session, parser, queryExplainer).process(node, null);
}
private static final class Visitor
extends AstVisitor<Node, Void>
{
private final Session session;
private final SqlParser parser;
private final Optional<QueryExplainer> queryExplainer;
public Visitor(
Session session,
SqlParser parser,
Optional<QueryExplainer> queryExplainer)
{
this.session = requireNonNull(session, "session is null");
this.parser = parser;
this.queryExplainer = requireNonNull(queryExplainer, "queryExplainer is null");
}
@Override
protected Node visitExplain(Explain node, Void context)
throws SemanticException
{
if (node.isAnalyze()) {
Statement statement = (Statement) process(node.getStatement(), context);
return new Explain(statement, node.isAnalyze(), node.getOptions());
}
ExplainType.Type planType = LOGICAL;
ExplainFormat.Type planFormat = TEXT;
List<ExplainOption> options = node.getOptions();
for (ExplainOption option : options) {
if (option instanceof ExplainType) {
planType = ((ExplainType) option).getType();
break;
}
}
for (ExplainOption option : options) {
if (option instanceof ExplainFormat) {
planFormat = ((ExplainFormat) option).getType();
break;
}
}
return getQueryPlan(node, planType, planFormat);
}
private Node getQueryPlan(Explain node, ExplainType.Type planType, ExplainFormat.Type planFormat)
throws IllegalArgumentException
{
Statement wrappedStatement = node.getStatement();
Statement statement = unwrapExecuteStatement(wrappedStatement, parser, session);
List<Expression> parameters = wrappedStatement instanceof Execute ? ((Execute) wrappedStatement).getParameters() : emptyList();
validateParameters(statement, parameters);
if (planType == VALIDATE) {
queryExplainer.get().analyze(session, statement, parameters);
return singleValueQuery("Valid", true);
}
String plan;
switch (planFormat) {
case GRAPHVIZ:
plan = queryExplainer.get().getGraphvizPlan(session, statement, planType, parameters);
break;
case TEXT:
plan = queryExplainer.get().getPlan(session, statement, planType, parameters);
break;
default:
throw new IllegalArgumentException("Invalid Explain Format: " + planFormat.toString());
}
return singleValueQuery("Query Plan", plan);
}
@Override
protected Node visitNode(Node node, Void context)
{
return node;
}
}
}