Hi
Please see attached file: I added method testConcurrentMergeDeadlock() to
existing test.
This test failed with error
...
Caused by: java.lang.IllegalStateException: Entry is locked [1.4.193/101]
at org.h2.mvstore.DataUtils.newIllegalStateException(DataUtils.java:766)
The same test with UPDATE instead of MERGE works fine.
Looks like MERGE removes lock previously acquired by SELECT FOR UPDATE
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/*
* Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.test.mvcc;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.concurrent.CountDownLatch;
import org.h2.api.ErrorCode;
import org.h2.test.TestBase;
import org.h2.util.Task;
/**
* Multi-threaded MVCC (multi version concurrency) test cases.
*/
public class TestMvccMultiThreaded extends TestBase {
/**
* Run just this test.
*
* @param a ignored
*/
public static void main(String... a) throws Exception {
TestBase.createCaller().init().test();
}
@Override
public void test() throws Exception {
testMergeWithUniqueKeyViolation();
// not supported currently
if (!config.multiThreaded) {
testConcurrentMerge();
testConcurrentUpdate();
testConcurrentMergeDeadlock();
}
}
private void testMergeWithUniqueKeyViolation() throws Exception {
deleteDb(getTestName());
Connection conn = getConnection(getTestName());
Statement stat = conn.createStatement();
stat.execute("create table test(x int primary key, y int unique)");
stat.execute("insert into test values(1, 1)");
assertThrows(ErrorCode.DUPLICATE_KEY_1, stat).
execute("merge into test values(2, 1)");
stat.execute("merge into test values(1, 2)");
conn.close();
}
private void testConcurrentMerge() throws Exception {
deleteDb(getTestName());
int len = 3;
final Connection[] connList = new Connection[len];
for (int i = 0; i < len; i++) {
Connection conn = getConnection(
getTestName() + ";MVCC=TRUE;LOCK_TIMEOUT=500");
connList[i] = conn;
}
Connection conn = connList[0];
conn.createStatement().execute(
"create table test(id int primary key, name varchar)");
Task[] tasks = new Task[len];
final boolean[] stop = { false };
for (int i = 0; i < len; i++) {
final Connection c = connList[i];
c.setAutoCommit(false);
tasks[i] = new Task() {
@Override
public void call() throws Exception {
while (!stop) {
c.createStatement().execute(
"merge into test values(1, 'x')");
c.commit();
Thread.sleep(1);
}
}
};
tasks[i].execute();
}
Thread.sleep(1000);
stop[0] = true;
for (int i = 0; i < len; i++) {
tasks[i].get();
}
for (int i = 0; i < len; i++) {
connList[i].close();
}
deleteDb(getTestName());
}
private void testConcurrentUpdate() throws Exception {
deleteDb(getTestName());
int len = 2;
final Connection[] connList = new Connection[len];
for (int i = 0; i < len; i++) {
connList[i] = getConnection(
getTestName() + ";MVCC=TRUE");
}
Connection conn = connList[0];
conn.createStatement().execute(
"create table test(id int primary key, value int)");
conn.createStatement().execute(
"insert into test values(0, 0)");
final int count = 1000;
Task[] tasks = new Task[len];
final CountDownLatch latch = new CountDownLatch(len);
for (int i = 0; i < len; i++) {
final int x = i;
tasks[i] = new Task() {
@Override
public void call() throws Exception {
for (int a = 0; a < count; a++) {
connList[x].createStatement().execute(
"update test set value=value+1");
latch.countDown();
latch.await();
}
}
};
