Server mode: concurrently using the same connection could throw an exception…

Server mode: concurrently using the same connection could throw an exception Connection is broken: unexpected status

h2/src/docsrc/html/changelog.html

@@ -21,6 +21,9 @@ Change Log
 
 <h2>Next Version (unreleased)</h2>
 <ul>
+<li>Server mode: concurrently using the same connection could throw an exception
+    "Connection is broken: unexpected status".
+</li>
 <li>Performance improvement for metadata queries that join against the COLUMNS metadata table.
 </li>
 <li>An ArrayIndexOutOfBoundsException was thrown in some cases

h2/src/main/org/h2/engine/SessionRemote.java

@@ -242,7 +242,7 @@ public class SessionRemote extends SessionWithState implements DataHandler {
         }
     }
 
-    private void setAutoCommitSend(boolean autoCommit) {
+    private synchronized void setAutoCommitSend(boolean autoCommit) {
         if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_8) {
             for (int i = 0, count = 0; i < transferList.size(); i++) {
                 Transfer transfer = transferList.get(i);

h2/src/test/org/h2/test/jdbc/TestConcurrentConnectionUsage.java

+/*
+ * 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.jdbc;
+
+import java.io.ByteArrayInputStream;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+import org.h2.test.TestBase;
+import org.h2.util.Task;
+
+/**
+ * Test concurrent usage of the same connection.
+ */
+public class TestConcurrentConnectionUsage 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 SQLException {
+        testAutoCommit();
+    }
+
+    private void testAutoCommit() throws SQLException {
+;        config.networked = true;
+        deleteDb(getTestName());
+        final Connection conn = getConnection(getTestName());
+        final PreparedStatement p1 = conn.prepareStatement("select 1 from dual");
+        Task t = new Task() {
+            @Override
+            public void call() throws Exception {
+                while (!stop) {
+                    p1.executeQuery();
+                    conn.setAutoCommit(true);
+                    conn.setAutoCommit(false);
+                }
+            }
+        }.execute();
+        PreparedStatement prep = conn.prepareStatement("select ? from dual");
+        for (int i = 0; i < 10; i++) {
+            prep.setBinaryStream(1, new ByteArrayInputStream(new byte[1024]));
+            prep.executeQuery();
+        }
+        t.get();
+        conn.close();
+    }
+
+}