New experimental database file locking mechanism "FS" to use native file locking.

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

@@ -507,7 +507,7 @@ public class Database implements DataHandler {
             traceSystem.getTrace(Trace.DATABASE)
                     .info("opening " + databaseName + " (build " + Constants.BUILD_ID + ")");
             if (autoServerMode) {
-                if (readOnly || fileLockMethod == FileLock.LOCK_NO || fileLockMethod == FileLock.LOCK_SERIALIZED) {
+                if (readOnly || fileLockMethod == FileLock.LOCK_NO || fileLockMethod == FileLock.LOCK_SERIALIZED || fileLockMethod == FileLock.LOCK_FS) {
                     throw DbException.getUnsupportedException("autoServerMode && (readOnly || fileLockMethod == NO" +
                             " || fileLockMethod == SERIALIZED)");
                 }
@@ -519,12 +519,14 @@ public class Database implements DataHandler {
                 }
             }
             if (!readOnly && fileLockMethod != FileLock.LOCK_NO) {
+                if (fileLockMethod != FileLock.LOCK_FS) {
                     lock = new FileLock(traceSystem, lockFileName, Constants.LOCK_SLEEP);
                     lock.lock(fileLockMethod);
                     if (autoServerMode) {
                         startServer(lock.getUniqueId());
                     }
                 }
+            }
             while (isReconnectNeeded() && !beforeWriting()) {
                 // wait until others stopped writing and
                 // until we can write (file are not open - no need to re-connect)
@@ -1142,7 +1144,7 @@ public class Database implements DataHandler {
         }
         reconnectModified(false);
         closeFiles();
-        if (persistent && lock == null && fileLockMethod != FileLock.LOCK_NO) {
+        if (persistent && lock == null && fileLockMethod != FileLock.LOCK_NO && fileLockMethod != FileLock.LOCK_FS) {
             // everything already closed (maybe in checkPowerOff)
             // don't delete temp files in this case because
             // the database could be open now (even from within another process)
@@ -2056,6 +2058,9 @@ public class Database implements DataHandler {
             if (pageSize != SysProperties.PAGE_SIZE) {
                 pageStore.setPageSize(pageSize);
             }
+            if (!readOnly && fileLockMethod == FileLock.LOCK_FS) {
+                pageStore.setLockFile(true);
+            }
             pageStore.open();
         }
         return pageStore;

h2/src/main/org/h2/store/FileLock.java

@@ -57,6 +57,11 @@ public class FileLock implements Runnable {
      */
     public static final int LOCK_SERIALIZED = 3;
 
+    /**
+     * Use the file system to lock the file; don't use a separate lock file.
+     */
+    public static final int LOCK_FS = 4;
+
     private static final String MAGIC = "FileLock";
     private static final String FILE = "file", SOCKET = "socket", SERIALIZED = "serialized";
     private static final int RANDOM_BYTES = 16;
@@ -134,6 +139,8 @@ public class FileLock implements Runnable {
         case LOCK_SERIALIZED:
             lockSerialized();
             break;
+        case LOCK_FS:
+            break;
         }
         locked = true;
     }
@@ -462,6 +469,8 @@ public class FileLock implements Runnable {
             return FileLock.LOCK_SOCKET;
         } else if (method.equalsIgnoreCase("SERIALIZED")) {
             return FileLock.LOCK_SERIALIZED;
+        } else if (method.equalsIgnoreCase("FS")) {
+            return FileLock.LOCK_FS;
         } else {
             throw DbException.get(ErrorCode.UNSUPPORTED_LOCK_METHOD_1, method);
         }

h2/src/main/org/h2/store/FileStore.java

@@ -509,4 +509,21 @@ public class FileStore {
         return textMode;
     }
 
+    /**
+     * Try to lock the file.
+     *
+     * @return true if successful
+     */
+    public boolean tryLock() {
+        return file.tryLock();
+    }
+
+    /**
+     * Release the file lock.
+     */
+    public void releaseLock() {
+        file.releaseLock();
+    }
+
+
 }

h2/src/main/org/h2/store/PageStore.java

@@ -184,6 +184,7 @@ public class PageStore implements CacheWriter {
     private long logSizeBase;
     private HashMap<String, Integer> statistics;
     private int logMode = LOG_MODE_SYNC;
+    private boolean lockFile;
 
     /**
      * Create a new page store object.
@@ -281,6 +282,7 @@ public class PageStore implements CacheWriter {
         setPageSize(pageSize);
         freeListPagesPerList = PageFreeList.getPagesAddressed(pageSize);
         file = database.openFile(fileName, accessMode, false);
+        lockFile();
         recoveryRunning = true;
         writeStaticHeader();
         writeVariableHeader();
@@ -294,8 +296,17 @@ public class PageStore implements CacheWriter {
         increaseFileSize();
     }
 
+    private void lockFile() {
+        if (lockFile) {
+            if (!file.tryLock()) {
+                throw DbException.get(ErrorCode.DATABASE_ALREADY_OPEN_1, fileName);
+            }
+        }
+    }
+
     private void openExisting() {
         file = database.openFile(fileName, accessMode, true);
+        lockFile();
         readStaticHeader();
         freeListPagesPerList = PageFreeList.getPagesAddressed(pageSize);
         fileLength = file.length();
@@ -304,6 +315,7 @@ public class PageStore implements CacheWriter {
             if (database.isReadOnly()) {
                 throw DbException.get(ErrorCode.FILE_CORRUPTED_1, fileName + " pageCount: " + pageCount);
             }
+            file.releaseLock();
             file.close();
             IOUtils.delete(fileName);
             openNew();
@@ -800,6 +812,7 @@ public class PageStore implements CacheWriter {
             }
             if (file != null) {
                 try {
+                    file.releaseLock();
                     file.close();
                 } finally {
                     file = null;
@@ -1304,7 +1317,7 @@ public class PageStore implements CacheWriter {
     void redoDelete(int logPos, int tableId, long key) {
         Index index = metaObjects.get(tableId);
         PageDataIndex scan = (PageDataIndex) index;
-        Row row = scan.getRow(key);
+        Row row = scan.getRowWithKey(key);
         redo(logPos, tableId, row, false);
     }
 
@@ -1729,4 +1742,8 @@ public class PageStore implements CacheWriter {
         return logMode;
     }
 
+    public void setLockFile(boolean lockFile) {
+        this.lockFile = lockFile;
+    }
+
 }

h2/src/main/org/h2/store/fs/FileObject.java

@@ -75,4 +75,16 @@ public interface FileObject {
      */
     String getName();
 
+    /**
+     * Try to lock the file exclusively.
+     *
+     * @return true if locking was successful
+     */
+    boolean tryLock();
+
+    /**
+     * Release the file lock.
+     */
+    void releaseLock();
+
 }

h2/src/main/org/h2/store/fs/FileObjectDisk.java

@@ -9,6 +9,7 @@ package org.h2.store.fs;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.RandomAccessFile;
+import java.nio.channels.FileLock;
 import org.h2.constant.SysProperties;
 import org.h2.util.IOUtils;
 
@@ -18,6 +19,7 @@ import org.h2.util.IOUtils;
 public class FileObjectDisk extends RandomAccessFile implements FileObject {
 
     private final String name;
+    private FileLock lock;
 
     FileObjectDisk(String fileName, String mode) throws FileNotFoundException {
         super(fileName, mode);
@@ -47,4 +49,27 @@ public class FileObjectDisk extends RandomAccessFile implements FileObject {
         return name;
     }
 
+    public synchronized boolean tryLock() {
+        if (lock == null) {
+            try {
+                lock = getChannel().tryLock();
+            } catch (Exception e) {
+                // could not lock (OverlappingFileLockException)
+            }
+            return lock != null;
+        }
+        return false;
+    }
+
+    public synchronized void releaseLock() {
+        if (lock != null) {
+            try {
+                lock.release();
+            } catch (IOException e) {
+                // ignore
+            }
+            lock = null;
+        }
+    }
+
 }

h2/src/main/org/h2/store/fs/FileObjectDiskChannel.java

@@ -11,6 +11,7 @@ import java.io.IOException;
 import java.io.RandomAccessFile;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
 
 /**
  * File which uses NIO FileChannel.
@@ -19,6 +20,7 @@ public class FileObjectDiskChannel implements FileObject {
 
     private final String name;
     private FileChannel channel;
+    private FileLock lock;
 
     FileObjectDiskChannel(String fileName, String mode) throws FileNotFoundException {
         this.name = fileName;
@@ -86,4 +88,27 @@ public class FileObjectDiskChannel implements FileObject {
         channel.write(buf);
     }
 
+    public synchronized boolean tryLock() {
+        if (lock == null) {
+            try {
+                lock = channel.tryLock();
+            } catch (IOException e) {
+                // could not lock
+            }
+            return lock != null;
+        }
+        return false;
+    }
+
+    public synchronized void releaseLock() {
+        if (lock != null) {
+            try {
+                lock.release();
+            } catch (IOException e) {
+                // ignore
+            }
+            lock = null;
+        }
+    }
+
 }

h2/src/main/org/h2/store/fs/FileObjectDiskMapped.java

@@ -13,6 +13,7 @@ import java.lang.ref.WeakReference;
 import java.lang.reflect.Method;
 import java.nio.BufferUnderflowException;
 import java.nio.MappedByteBuffer;
+import java.nio.channels.FileLock;
 import java.nio.channels.FileChannel.MapMode;
 import org.h2.constant.SysProperties;
 import org.h2.util.IOUtils;
@@ -28,6 +29,7 @@ public class FileObjectDiskMapped implements FileObject {
     private final MapMode mode;
     private RandomAccessFile file;
     private MappedByteBuffer mapped;
+    private FileLock lock;
 
     /**
      * The position within the file. Can't use the position of the mapped buffer
@@ -180,4 +182,27 @@ public class FileObjectDiskMapped implements FileObject {
         pos += len;
     }
 
+    public synchronized boolean tryLock() {
+        if (lock == null) {
+            try {
+                lock = file.getChannel().tryLock();
+            } catch (IOException e) {
+                // could not lock
+            }
+            return lock != null;
+        }
+        return false;
+    }
+
+    public synchronized void releaseLock() {
+        if (lock != null) {
+            try {
+                lock.release();
+            } catch (IOException e) {
+                // ignore
+            }
+            lock = null;
+        }
+    }
+
 }

h2/src/main/org/h2/store/fs/FileObjectMemory.java

@@ -69,4 +69,12 @@ public class FileObjectMemory implements FileObject {
         return data.getLastModified();
     }
 
+    public boolean tryLock() {
+        return data.tryLock();
+    }
+
+    public void releaseLock() {
+        data.releaseLock();
+    }
+
 }

h2/src/main/org/h2/store/fs/FileObjectMemoryData.java

@@ -37,6 +37,7 @@ class FileObjectMemoryData {
     private byte[][] data;
     private long lastModified;
     private boolean isReadOnly;
+    private volatile boolean locked;
 
     static {
         byte[] n = new byte[BLOCK_SIZE];
@@ -295,4 +296,24 @@ class FileObjectMemoryData {
         return true;
     }
 
+    /**
+     * Lock the file.
+     *
+     * @return if successful
+     */
+    synchronized boolean tryLock() {
+        if (locked) {
+            return false;
+        }
+        locked = true;
+        return true;
+    }
+
+    /**
+     * Unlock the file.
+     */
+    public synchronized void releaseLock() {
+        locked = false;
+    }
+
 }

h2/src/main/org/h2/store/fs/FileObjectSplit.java

@@ -152,4 +152,12 @@ public class FileObjectSplit implements FileObject {
         return name;
     }
 
+    public boolean tryLock() {
+        return list[0].tryLock();
+    }
+
+    public void releaseLock() {
+        list[0].releaseLock();
+    }
+
 }

h2/src/main/org/h2/store/fs/FileObjectZip.java

@@ -107,4 +107,12 @@ public class FileObjectZip implements FileObject {
         return file.getName();
     }
 
+    public boolean tryLock() {
+        return false;
+    }
+
+    public void releaseLock() {
+        // ignore
+    }
+
 }

h2/src/test/org/h2/test/synth/TestPowerOffFs.java

@@ -11,7 +11,6 @@ import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.sql.Statement;
 import org.h2.constant.ErrorCode;
-import org.h2.store.fs.FileSystem;
 import org.h2.test.TestBase;
 import org.h2.test.utils.DebugFileSystem;
 
@@ -32,8 +31,7 @@ public class TestPowerOffFs extends TestBase {
     }
 
     public void test() throws Exception {
-        DebugFileSystem.register();
-        fs = (DebugFileSystem) FileSystem.getInstance("debug:/");
+        fs = DebugFileSystem.register();
         test(Integer.MAX_VALUE);
         System.out.println(Integer.MAX_VALUE - fs.getPowerOffCount());
         System.out.println("done");

h2/src/test/org/h2/test/synth/TestPowerOffFs2.java

@@ -14,7 +14,6 @@ import java.sql.Statement;
 import java.util.ArrayList;
 import java.util.Random;
 import org.h2.constant.ErrorCode;
-import org.h2.store.fs.FileSystem;
 import org.h2.test.TestBase;
 import org.h2.test.utils.DebugFileSystem;
 import org.h2.util.New;
@@ -44,9 +43,8 @@ public class TestPowerOffFs2 extends TestBase {
     }
 
     public void test() throws Exception {
-        DebugFileSystem.register();
+        fs = DebugFileSystem.register();
         url = "jdbc:h2:debug:memFS:powerOffFs;FILE_LOCK=NO;TRACE_LEVEL_FILE=0;WRITE_DELAY=0;CACHE_SIZE=32";
-        fs = (DebugFileSystem) FileSystem.getInstance("debug:/");
         for (int i = 0;; i++) {
             test(i);
         }

h2/src/test/org/h2/test/unit/FileObjectDatabase.java

@@ -90,4 +90,12 @@ public class FileObjectDatabase implements FileObject {
         return fileName;
     }
 
+    public void releaseLock() {
+        // ignore
+    }
+
+    public boolean tryLock() {
+        return false;
+    }
+
 }

h2/src/test/org/h2/test/unit/TestFileLock.java

@@ -7,6 +7,10 @@
 package org.h2.test.unit;
 
 import java.io.File;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import org.h2.constant.ErrorCode;
 import org.h2.engine.Constants;
 import org.h2.message.TraceSystem;
 import org.h2.store.FileLock;
@@ -50,12 +54,26 @@ public class TestFileLock extends TestBase implements Runnable {
         if (!getFile().startsWith(TestBase.BASE_TEST_DIR)) {
             return;
         }
+        testFsFileLock();
         testFutureModificationDate();
         testSimple();
         test(false);
         test(true);
     }
 
+    private void testFsFileLock() throws Exception {
+        deleteDb("fileLock");
+        String url = "jdbc:h2:" + getBaseDir() + "/fileLock;FILE_LOCK=FS;OPEN_NEW=TRUE";
+        Connection conn = DriverManager.getConnection(url);
+        try {
+            DriverManager.getConnection(url);
+            fail();
+        } catch (SQLException e) {
+            assertEquals(ErrorCode.DATABASE_ALREADY_OPEN_1, e.getErrorCode());
+        }
+        conn.close();
+    }
+
     private void testFutureModificationDate() throws Exception {
         File f = new File(getFile());
         f.delete();

h2/src/test/org/h2/test/unit/TestPageStore.java

@@ -38,6 +38,7 @@ public class TestPageStore extends TestBase implements DatabaseEventListener {
     }
 
     public void test() throws Exception {
+        testInsertReverse();
         testInsertDelete();
         testCheckpoint();
         testDropRecreate();
@@ -64,6 +65,19 @@ public class TestPageStore extends TestBase implements DatabaseEventListener {
         deleteDb("pageStore");
     }
 
+    private void testInsertReverse() throws SQLException {
+        deleteDb("pageStore");
+        Connection conn;
+        conn = getConnection("pageStore");
+        Statement stat = conn.createStatement();
+        stat.execute("create table test(id int primary key, data varchar)");
+        stat.execute("insert into test select -x, space(100) from system_range(1, 1000)");
+        stat.execute("drop table test");
+        stat.execute("create table test(id int primary key, data varchar)");
+        stat.execute("insert into test select -x, space(2048) from system_range(1, 1000)");
+        conn.close();
+    }
+
     private void testInsertDelete() {
         Row[] x = new Row[0];
         Row r = new Row(null, 0);

h2/src/test/org/h2/test/utils/DebugFileObject.java

@@ -87,4 +87,15 @@ public class DebugFileObject implements FileObject {
             throw e;
         }
     }
+
+    public boolean tryLock() {
+        debug("tryLock");
+        return file.tryLock();
+    }
+
+    public void releaseLock() {
+        debug("releaseLock");
+        file.releaseLock();
+    }
+
 }

h2/src/test/org/h2/test/utils/DebugFileSystem.java

@@ -33,8 +33,9 @@ public class DebugFileSystem extends FileSystem {
     /**
      * Register the file system.
      */
-    public static void register() {
+    public static DebugFileSystem register() {
         FileSystem.register(INSTANCE);
+        return INSTANCE;
     }
 
     /**

h2/src/test/org/h2/test/utils/RecordingFileObject.java

@@ -67,4 +67,12 @@ public class RecordingFileObject implements FileObject {
         fs.log(Recorder.WRITE, name, buff, file.getFilePointer());
     }
 
+    public boolean tryLock() {
+        return file.tryLock();
+    }
+
+    public void releaseLock() {
+        file.releaseLock();
+    }
+
 }