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/*
*
* Derby - Class DeadlockModeTest
*
* 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.derbyTesting.functionTests.tests.lang;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.LinkedList;
import junit.framework.Test;
import org.apache.derbyTesting.junit.BaseJDBCTestCase;
import org.apache.derbyTesting.junit.BaseTestSuite;
import org.apache.derbyTesting.junit.CleanDatabaseTestSetup;
import org.apache.derbyTesting.junit.DatabasePropertyTestSetup;
import org.apache.derbyTesting.junit.Decorator;
import org.apache.derbyTesting.junit.JDBC;
/**
* This tests for deadlock which can occur if two threads get a
* row lock before getting a table lock on the same table. This can
* happen if the lock obtained by the insert, update or delete result set
* is a smaller range than the table scan result set. The insert, update or
* delete result set lock is obtained first. For example, if the insert, update
* or delete result set obtain a row lock and then the table scan obtains a
* table scan lock, deadlock can occur since two threads can obtain the row lock
* and then both thread will want the same table lock.
*/
public class DeadlockModeTest extends BaseJDBCTestCase {
/* Number of threads to use */
private static final int THREAD_COUNT = 20;
/* Object used to manage the thread synching */
private Object syncObject = new Object();
/* Amount of threads started so far */
private int startedCount = 0;
/* Exceptions thrown by threads (if any) */
private LinkedList<Exception> listExceptions = new LinkedList<Exception>();
/**
* Creates a new instance of DeadlockModeTest
* @param name identifier of the test
*/
public DeadlockModeTest(String name) {
super(name);
}
/**
* Tests for a deadlock on concurrent accesses to the database
*/
public void testThreadsUpdatingTable() throws Exception {
Thread [] t = new Thread[THREAD_COUNT];
createThreads(t);
waitForThreads(t);
if ( !listExceptions.isEmpty() ) {
fail("FAIL - " + listExceptions.size() + " threads threw exceptions");
}
}
/**
* This method creates THREAD_COUNT threads which will all try to
* update the same table
*/
private void createThreads(Thread [] t) throws SQLException {
for (int i = 0; i < THREAD_COUNT; i++)
{
final Connection c = openDefaultConnection();
t[i] = new Thread(new Runnable() {
public void run() {threadWorker(c); }});
t[i].start();
}
}
/**
* This method waits for the threads to finish their execution.
* This call will block the execution until signaled otherwise.
*/
private void waitForThreads(Thread [] t) throws Exception {
for (int i = 0; i < THREAD_COUNT; i++)
{
try {
t[i].join();
} catch (InterruptedException e){
assertNull(
"FAIL - Exception thrown waiting for the threads",
e);
}
}
}
/**
* This method has the code that each thread will be running.
* Since this will be running within different threads, we
* can not throw exceptions, therefore we make a "bogus"
* assertNull(string message,Exception e) call.
*/
private void threadWorker(Connection threadConnection) {
try {
synchronized (syncObject) {
/* A new thread started, so we increment the counter */
startedCount++;
/* Wake all the threads to run the check below */
syncObject.notifyAll();
while (startedCount < THREAD_COUNT) {
syncObject.wait();
}
}
Statement stmt = threadConnection.createStatement();
/* execute a query to load cache */
stmt.executeUpdate("update t set i = 456 where i = 456");
threadConnection.setAutoCommit(false);
/* set isolation level to serializable */
stmt.execute("set isolation serializable");
for (int i = 0; i < 100 ; i++) {
stmt.executeUpdate("update t set i = 456 where i = 456");
threadConnection.commit();
}
threadConnection.close();
} catch (Exception e) {
synchronized(syncObject){
listExceptions.add(e);
}
}
}
protected static Test baseSuite(String name) {
BaseTestSuite suite = new BaseTestSuite(name);
suite.addTestSuite(DeadlockModeTest.class);
return new CleanDatabaseTestSetup(
DatabasePropertyTestSetup.setLockTimeouts(suite, 2, 4))
{
/**
* Creates the tables used in the test cases.
* @exception SQLException if a database error occurs
*/
protected void decorateSQL(Statement stmt) throws SQLException
{
stmt.execute("create table t (i int)");
stmt.executeUpdate("insert into t values (1956)");
stmt.executeUpdate("insert into t values (180)");
stmt.executeUpdate("insert into t values (3)");
}
};
}
public static Test suite() {
BaseTestSuite suite = new BaseTestSuite("DeadlockModeTest ");
suite.addTest(
baseSuite("DeadlockModeTest:embedded")
);
/* JSR169 does not have encryption support */
if ( JDBC.vmSupportsJDBC3() ) {
suite.addTest(Decorator.encryptedDatabase(
baseSuite("DeadlockModeTest:encrypted")));
}
return suite;
}
}
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