Improved order of file operations

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

@@ -138,7 +138,6 @@ public class FileStore {
                 file = new FilePathEncrypt.FileEncrypt(fileName, key, file);
             }
             file = FilePathCache.wrap(file);
-            fileSize = file.size();
             try {
                 if (readOnly) {
                     fileLock = file.tryLock(0, Long.MAX_VALUE, true);
@@ -153,6 +152,7 @@ public class FileStore {
                 throw DataUtils.newIllegalStateException(
                         DataUtils.ERROR_FILE_LOCKED, "The file is locked: {0}", fileName);
             }
+            fileSize = file.size();
         } catch (IOException e) {
             throw DataUtils.newIllegalStateException(
                     DataUtils.ERROR_READING_FAILED,

h2/src/main/org/h2/mvstore/db/MVTable.java

@@ -406,6 +406,14 @@ public class MVTable extends TableBase {
         }
         if (index.needRebuild()) {
             try {
+                // TODO Speed up creating an index, for example as follows: Read
+                // up to about 1 MB of entries in memory, sort them (detect
+                // duplicates here), write to a new map (in sorted order);
+                // repeat (using a new map for every block of 1 MB) until all
+                // record are read. Merge all maps to the target (using merge
+                // sort; duplicates are detected in the target). This is similar
+                // to a LSM tree. For randomly ordered data, this should use
+                // much less write operations than the current algorithm.
                 Index scan = getScanIndex(session);
                 long remaining = scan.getRowCount(session);
                 long total = remaining;

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

@@ -245,16 +245,15 @@ public class FilePathDisk extends FilePath {
 
     @Override
     public void createDirectory() {
-        File f = new File(name);
-        if (f.exists()) {
-            if (f.isDirectory()) {
-                return;
-            }
-            throw DbException.get(ErrorCode.FILE_CREATION_FAILED_1, name + " (a file with this name already exists)");
-        }
         File dir = new File(name);
         for (int i = 0; i < SysProperties.MAX_FILE_RETRY; i++) {
-            if ((dir.exists() && dir.isDirectory()) || dir.mkdir()) {
+            if (dir.exists()) {
+                if (dir.isDirectory()) {
+                    return;
+                }
+                throw DbException.get(ErrorCode.FILE_CREATION_FAILED_1, 
+                        name + " (a file with this name already exists)");
+            } else if (dir.mkdir()) {
                 return;
             }
             wait(i);

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

@@ -157,8 +157,6 @@ public class FilePathEncrypt extends FilePathWrapper {
 
         private final FileChannel base;
 
-        private final XTS xts;
-
         /**
          * The current position within the file, from a user perspective.
          */
@@ -171,9 +169,23 @@ public class FilePathEncrypt extends FilePathWrapper {
 
         private final String name;
         
-        public FileEncrypt(String name, byte[] encryptionKey, FileChannel base) throws IOException {
+        private XTS xts;
+
+        private byte[] encryptionKey;
+
+        public FileEncrypt(String name, byte[] encryptionKey, FileChannel base) {
+            // don't do any read or write operations here, because they could
+            // fail if the file is locked, and we want to give the caller a
+            // chance to lock the file first
             this.name = name;
             this.base = base;
+            this.encryptionKey = encryptionKey;
+        }
+        
+        private void init() throws IOException {
+            if (xts != null) {
+                return;
+            }
             this.size = base.size() - HEADER_LENGTH;
             boolean newFile = size < 0;
             byte[] salt;
@@ -192,6 +204,7 @@ public class FilePathEncrypt extends FilePathWrapper {
             }
             AES cipher = new AES();
             cipher.setKey(SHA256.getPBKDF2(encryptionKey, salt, HASH_ITERATIONS, 16));
+            encryptionKey = null;
             xts = new XTS(cipher);
         }
 
@@ -226,6 +239,7 @@ public class FilePathEncrypt extends FilePathWrapper {
             if (len == 0) {
                 return 0;
             }
+            init();
             len = (int) Math.min(len, size - position);
             if (position >= size) {
                 return -1;
@@ -274,6 +288,7 @@ public class FilePathEncrypt extends FilePathWrapper {
 
         @Override
         public int write(ByteBuffer src, long position) throws IOException {
+            init();
             int len = src.remaining();
             if ((position & BLOCK_SIZE_MASK) != 0 ||
                     (len & BLOCK_SIZE_MASK) != 0) {
@@ -343,11 +358,13 @@ public class FilePathEncrypt extends FilePathWrapper {
 
         @Override
         public long size() throws IOException {
+            init();
             return size;
         }
 
         @Override
         public FileChannel truncate(long newSize) throws IOException {
+            init();
             if (newSize > size) {
                 return this;
             }