MVStore: concurrency problems have been fixed.

h2/src/docsrc/html/changelog.html

@@ -19,6 +19,7 @@ Change Log
 
 <h2>Next Version (unreleased)</h2>
 <ul><li>Issue 73: MySQL compatibility: support REPLACE, patch by Cemo Koc.
+</li><li>MVStore: concurrency problems have been fixed.
 </li></ul>
 
 <h2>Version 1.3.174 (2013-10-19)</h2>

h2/src/installer/release.txt

@@ -28,4 +28,5 @@ Add to http://freecode.com/
 Add to http://twitter.com
 - tweet: add @geospatialnews for the new geometry type and disk spatial index
 Close bugs: http://code.google.com/p/h2database/issues/list
+Update statistics
 

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

@@ -396,7 +396,7 @@ public class DataUtils {
             }
             throw newIllegalStateException(
                     ERROR_READING_FAILED,
-                    "Reading from {0} failed; file length {1} read length {1} at {2}",
+                    "Reading from {0} failed; file length {1} read length {2} at {3}",
                     file, size, dst.remaining(), pos, e);
         }
     }

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

@@ -214,7 +214,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      */
     @SuppressWarnings("unchecked")
     public K getKey(long index) {
-        checkOpen();
         if (index < 0 || index >= size()) {
             return null;
         }
@@ -285,7 +284,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      * @return the index
      */
     public long getKeyIndex(K key) {
-        checkOpen();
         if (size() == 0) {
             return -1;
         }
@@ -319,7 +317,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      */
     @SuppressWarnings("unchecked")
     protected K getFirstLast(boolean first) {
-        checkOpen();
         if (size() == 0) {
             return null;
         }
@@ -383,7 +380,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      * @return the key, or null if no such key exists
      */
     protected K getMinMax(K key, boolean min, boolean excluding) {
-        checkOpen();
         return getMinMax(root, key, min, excluding);
     }
 
@@ -429,7 +425,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
     @Override
     @SuppressWarnings("unchecked")
     public V get(Object key) {
-        checkOpen();
         return (V) binarySearch(root, key);
     }
 
@@ -514,7 +509,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      * Remove all entries, and close the map.
      */
     public void removeMap() {
-        checkOpen();
+        int todoMoveToMVStore;
         if (this == store.getMetaMap()) {
             return;
         }
@@ -712,7 +707,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
                 } else {
                     list.add(root);
                 }
-                store.markChanged(this);
             }
             root = newRoot;
         }
@@ -775,7 +769,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      * @return the iterator
      */
     public Cursor<K> keyIterator(K from) {
-        checkOpen();
         return new Cursor<K>(this, root, from);
     }
 
@@ -790,7 +783,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
 
     @Override
     public Set<K> keySet() {
-        checkOpen();
         final MVMap<K, V> map = this;
         final Page root = this.root;
         return new AbstractSet<K>() {
@@ -831,7 +823,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
         return store.getMapName(id);
     }
 
-    public MVStore getStore() {
+    MVStore getStore() {
         return store;
     }
 
@@ -897,18 +889,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
         return readOnly;
     }
 
-    /**
-     * Check whether the map is open.
-     *
-     * @throws IllegalStateException if the map is closed
-     */
-    protected void checkOpen() {
-        if (closed) {
-            throw DataUtils.newIllegalStateException(
-                    DataUtils.ERROR_CLOSED, "This map is closed");
-        }
-    }
-
     /**
      * This method is called before writing to the map. The default
      * implementation checks whether writing is allowed, and tries
@@ -918,8 +898,11 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      *      or if another thread is concurrently writing
      */
     protected void beforeWrite() {
+        if (closed) {
+            throw DataUtils.newIllegalStateException(
+                    DataUtils.ERROR_CLOSED, "This map is closed");
+        }
         if (readOnly) {
-            checkOpen();
             throw DataUtils.newUnsupportedOperationException(
                     "This map is read-only");
         }
@@ -991,14 +974,12 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      * @return the number of entries
      */
     public long sizeAsLong() {
-        checkOpen();
         return root.getTotalCount();
     }
 
     @Override
     public boolean isEmpty() {
         // could also use (sizeAsLong() == 0)
-        checkOpen();
         return root.isLeaf() && root.getKeyCount() == 0;
     }
 
@@ -1061,7 +1042,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      *
      * @return the opened map
      */
-    protected MVMap<K, V> openReadOnly() {
+    MVMap<K, V> openReadOnly() {
         MVMap<K, V> m = new MVMap<K, V>(keyType, valueType);
         m.readOnly = true;
         HashMap<String, String> config = New.hashMap();
@@ -1140,6 +1121,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      * @param newMapName the name name
      */
     public void renameMap(String newMapName) {
+        int todoMoveToMVStore;
         beforeWrite();
         try {
             store.renameMap(this, newMapName);

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

@@ -47,7 +47,7 @@ Documentation
 TestMVStoreDataLoss
 
 MVTableEngine:
-- use StreamStore
+- use StreamStore to avoid deadlocks
 - when the MVStore was enabled before, use it again
     (probably by checking existence of the mvstore file)
 - not use the .h2.db file
@@ -56,7 +56,6 @@ MVTableEngine:
 TransactionStore:
 
 MVStore:
-- rename FilePathCrypt to FilePathCipher
 - automated 'kill process' and 'power failure' test
 - update checkstyle
 - auto-compact from time to time and on close
@@ -107,11 +106,14 @@ MVStore:
 - storage that splits database into multiple files,
     to speed up compact and allow using trim
     (by truncating / deleting empty files)
-- add new feature to file systems that avoid copying data
-    (reads should return a ByteBuffer, not write into one)
+- add new feature to the file system API to avoid copying data
+    (reads that returns a ByteBuffer instead of writing into one)
+    for memory mapped files and off-heap storage
 - do we need to store a dummy chunk entry in the chunk itself?
     currently yes, as some fields are not set in the chunk header
-- off-heap LIRS cache (the LIRS cache should use a map factory)
+- support log structured merge style operations (blind writes)
+    using one map per level plus bloom filter
+- have a strict call order MVStore -> MVMap -> Page -> FileStore
 
 */
 
@@ -207,6 +209,7 @@ public class MVStore {
 
     private int unsavedPageCount;
     private int unsavedPageCountMax;
+    private boolean storeNeeded;
 
     /**
      * The time the store was created, in milliseconds since 1970.
@@ -427,9 +430,9 @@ public class MVStore {
             c.put("createVersion", Long.toString(currentVersion));
             map = builder.create();
             map.init(this, c);
+            markMetaChanged();
             meta.put("map." + id, map.asString(name));
             meta.put("name." + name, Integer.toString(id));
-            markMetaChanged();
             root = 0;
         }
         map.setRootPos(root, -1);
@@ -439,8 +442,11 @@ public class MVStore {
 
     /**
      * Get the metadata map. This data is for informational purposes only. The
-     * data is subject to change in future versions. The data should not be
-     * modified (doing so may corrupt the store).
+     * data is subject to change in future versions.
+     * <p>
+     * The data should not be modified (doing so may corrupt the store). Writing
+     * to it is not always detected as a modification, so that changes to it
+     * might not be stored.
      * <p>
      * It contains the following entries:
      * 
@@ -502,21 +508,10 @@ public class MVStore {
         return meta.containsKey("name." + name);
     }
 
-    /**
-     * Mark a map as changed (containing unsaved changes).
-     *
-     * @param map the map
-     */
-    void markChanged(MVMap<?, ?> map) {
-        if (map == meta) {
-            metaChanged = true;
-        }
-    }
-
     private void markMetaChanged() {
         // changes in the metadata alone are usually not detected, as the meta
         // map is changed after storing
-        markChanged(meta);
+        metaChanged = true;
     }
 
     private void readMeta() {
@@ -892,6 +887,10 @@ public class MVStore {
         for (MVMap<?, ?> m : list) {
             m.setWriteVersion(version);
             long v = m.getVersion();
+            if (m.getCreateVersion() > storeVersion) {
+                // the map was created after storing started
+                continue;
+            }
             if (v >= 0 && v >= lastStoredVersion) {
                 m.waitUntilWritten(storeVersion);
                 MVMap<?, ?> r = m.openVersion(storeVersion);
@@ -1203,6 +1202,7 @@ public class MVStore {
         }
         for (Chunk c : free) {
             chunks.remove(c.id);
+            markMetaChanged();
             meta.remove("chunk." + c.id);
             int length = MathUtils.roundUpInt(c.length, BLOCK_SIZE) + BLOCK_SIZE;
             fileStore.free(c.start, length);
@@ -1237,6 +1237,7 @@ public class MVStore {
             buff.position(0);
             fileStore.writeFully(end, buff.getBuffer());
             releaseWriteBuffer(buff);
+            markMetaChanged();
             meta.put("chunk." + c.id, c.asString());
         }
         boolean oldReuse = reuseSpace;
@@ -1273,6 +1274,7 @@ public class MVStore {
             buff.position(0);
             fileStore.writeFully(pos, buff.getBuffer());
             releaseWriteBuffer(buff);
+            markMetaChanged();
             meta.put("chunk." + c.id, c.asString());
         }
 
@@ -1501,11 +1503,15 @@ public class MVStore {
     }
 
     private void registerFreePage(long version, int chunkId, long maxLengthLive, int pageCount) {
-        HashMap<Integer, Chunk>freed = freedPageSpace.get(version);
+        HashMap<Integer, Chunk> freed = freedPageSpace.get(version);
         if (freed == null) {
             freed = New.hashMap();
-            freedPageSpace.put(version, freed);
+            HashMap<Integer, Chunk> f2 = freedPageSpace.putIfAbsent(version, freed);
+            if (f2 != null) {
+                freed = f2;
             }
+        }
+        synchronized (freed) {
             Chunk f = freed.get(chunkId);
             if (f == null) {
                 f = new Chunk(chunkId);
@@ -1514,6 +1520,7 @@ public class MVStore {
             f.maxLengthLive -= maxLengthLive;
             f.pageCountLive -= pageCount;
         }
+    }
 
     Compressor getCompressor() {
         return compressor;
@@ -1679,17 +1686,17 @@ public class MVStore {
      */
     void registerUnsavedPage() {
         unsavedPageCount++;
+        if (unsavedPageCount > unsavedPageCountMax && unsavedPageCountMax > 0) {
+            storeNeeded = true;
+        }
     }
 
     /**
      * This method is called before writing to a map.
      */
     void beforeWrite() {
-        if (currentStoreVersion >= 0) {
-            // store is possibly called within store, if the meta map changed
-            return;
-        }
-        if (unsavedPageCount > unsavedPageCountMax && unsavedPageCountMax > 0) {
+        if (storeNeeded) {
+            storeNeeded = false;
             store(true);
         }
     }
@@ -1819,6 +1826,7 @@ public class MVStore {
         // rollback might have rolled back the stored chunk metadata as well
         Chunk c = chunks.get(lastChunkId - 1);
         if (c != null) {
+            markMetaChanged();
             meta.put("chunk." + c.id, c.asString());
         }
         currentVersion = version;

h2/src/main/org/h2/mvstore/rtree/MVRTreeMap.java

@@ -52,7 +52,6 @@ public class MVRTreeMap<V> extends MVMap<SpatialKey, V> {
     @Override
     @SuppressWarnings("unchecked")
     public V get(Object key) {
-        checkOpen();
         return (V) get(root, key);
     }
 
@@ -63,7 +62,6 @@ public class MVRTreeMap<V> extends MVMap<SpatialKey, V> {
      * @return the iterator
      */
     public RTreeCursor findIntersectingKeys(SpatialKey x) {
-        checkOpen();
         return new RTreeCursor(root, x) {
             @Override
             protected boolean check(boolean leaf, SpatialKey key, SpatialKey test) {
@@ -79,7 +77,6 @@ public class MVRTreeMap<V> extends MVMap<SpatialKey, V> {
      * @return the iterator
      */
     public RTreeCursor findContainedKeys(SpatialKey x) {
-        checkOpen();
         return new RTreeCursor(root, x) {
             @Override
             protected boolean check(boolean leaf, SpatialKey key, SpatialKey test) {

h2/src/test/org/h2/test/TestAll.java

@@ -233,7 +233,7 @@ java org.h2.test.TestAll timer
 */
 
     ;
-    private static final boolean MV_STORE = false;
+    private static final boolean MV_STORE = true;
 
     /**
      * If the test should run with many rows.
@@ -470,7 +470,7 @@ kill -9 `jps -l | grep "org.h2.test." | cut -d " " -f 1`
             prof.interval = 1;
             prof.startCollecting();
             if (test.mvStore) {
-                TestPerformance.main("-init", "-db", "9", "-size", "1000");
+                TestPerformance.main("-init", "-db", "9", "-size", "10000");
             } else {
                 TestPerformance.main("-init", "-db", "1");
             }
@@ -481,7 +481,7 @@ kill -9 `jps -l | grep "org.h2.test." | cut -d " " -f 1`
                 prof.depth = 16;
                 prof.interval = 1;
                 prof.startCollecting();
-                TestPerformance.main("-init", "-db", "1", "-size", "1000");
+                TestPerformance.main("-init", "-db", "1", "-size", "10000");
                 prof.stopCollecting();
                 System.out.println(prof.getTop(3));
             }

h2/src/test/org/h2/test/store/TestConcurrent.java

@@ -10,6 +10,7 @@ import java.io.ByteArrayOutputStream;
 import java.io.FileOutputStream;
 import java.io.InputStream;
 import java.nio.channels.FileChannel;
+import java.util.ArrayList;
 import java.util.ConcurrentModificationException;
 import java.util.Iterator;
 import java.util.Map;
@@ -23,6 +24,7 @@ import org.h2.mvstore.MVStore;
 import org.h2.store.fs.FileChannelInputStream;
 import org.h2.store.fs.FileUtils;
 import org.h2.test.TestBase;
+import org.h2.upgrade.v1_1.util.New;
 import org.h2.util.Task;
 
 /**
@@ -41,9 +43,12 @@ public class TestConcurrent extends TestMVStore {
 
     @Override
     public void test() throws Exception {
+        
         FileUtils.deleteRecursive(getBaseDir(), true);
         FileUtils.createDirectories(getBaseDir());
+        FileUtils.deleteRecursive("memFS:", false);
 
+        testConcurrentFree();
         testConcurrentStoreAndRemoveMap();
         testConcurrentStoreAndClose();
         testConcurrentOnlineBackup();
@@ -53,65 +58,149 @@ public class TestConcurrent extends TestMVStore {
         testConcurrentRead();
     }
     
+    private void testConcurrentFree() throws InterruptedException {
+        String fileName = "memFS:testConcurrentFree.h3";
+        for (int test = 0; test < 10; test++) {
+            FileUtils.delete(fileName);
+            final MVStore s1 = new MVStore.Builder().
+                    fileName(fileName).writeDelay(-1).open();
+            s1.setRetentionTime(0);
+            final int count = 200;
+            for (int i = 0; i < count; i++) {
+                MVMap<Integer, Integer> m = s1.openMap("d" + i);
+                m.put(1, 1);
+                if (i % 2 == 0) {
+                    s1.store();
+                }
+            }
+            s1.store();
+            s1.close();
+            final MVStore s = new MVStore.Builder().
+                    fileName(fileName).writeDelay(-1).open();
+            s.setRetentionTime(0);
+            final ArrayList<MVMap<Integer, Integer>> list = New.arrayList();
+            for (int i = 0; i < count; i++) {
+                MVMap<Integer, Integer> m = s.openMap("d" + i);
+                list.add(m);
+            }
+            
+            final AtomicInteger counter = new AtomicInteger();
+            Task task = new Task() {
+                @Override
+                public void call() throws Exception {
+                    while (!stop) {
+                        int x = counter.getAndIncrement();
+                        if (x >= count) {
+                            break;
+                        }
+                        MVMap<Integer, Integer> m = list.get(x);
+                        m.clear();
+                        m.removeMap();
+                    }
+                }
+            };
+            task.execute();
+            Thread.sleep(1);
+            while (true) {
+                int x = counter.getAndIncrement();
+                if (x >= count) {
+                    break;
+                }
+                MVMap<Integer, Integer> m = list.get(x);
+                m.clear();
+                m.removeMap();
+                if (x % 5 == 0) {
+                    s.incrementVersion();
+                }
+            }
+            task.get();
+            s.store();
+            
+            MVMap<String, String> meta = s.getMetaMap();
+            int chunkCount = 0;
+            for (String k : meta.keyList()) {
+                if (k.startsWith("chunk.")) {
+                    chunkCount++;
+                }
+            }
+            assertEquals(1, chunkCount);
+            
+            s.close();
+        }
+    }
+
     private void testConcurrentStoreAndRemoveMap() throws InterruptedException {
-        String fileName = getBaseDir() + "/testConcurrentStoreAndRemoveMap.h3";
+        String fileName = "memFS:testConcurrentStoreAndRemoveMap.h3";
         final MVStore s = openStore(fileName);
-        int count = 100;
+        int count = 200;
         for (int i = 0; i < count; i++) {
             MVMap<Integer, Integer> m = s.openMap("d" + i);
             m.put(1, 1);
         }
+        final AtomicInteger counter = new AtomicInteger();
         Task task = new Task() {
             @Override
             public void call() throws Exception {
                 while (!stop) {
+                    counter.incrementAndGet();
                     s.store();
                 }
             }
         };
         task.execute();
         Thread.sleep(1);
-        for (int i = 0; i < count; i++) {
+        for (int i = 0; i < count || counter.get() < count; i++) {
             MVMap<Integer, Integer> m = s.openMap("d" + i);
             m.put(1, 10);
             m.removeMap();
+            if (task.isFinished()) {
+                break;
+            }
         }
         task.get();
         s.close();
     }
 
     private void testConcurrentStoreAndClose() throws InterruptedException {
-        String fileName = getBaseDir() + "/testConcurrentStoreAndClose.h3";
+        String fileName = "memFS:testConcurrentStoreAndClose";
+        for (int i = 0; i < 10; i++) {
+            FileUtils.delete(fileName);
             final MVStore s = openStore(fileName);
+            final AtomicInteger counter = new AtomicInteger();
             Task task = new Task() {
                 @Override
                 public void call() throws Exception {
-                int x = 0;
                     while (!stop) {
-                    s.setStoreVersion(x++);
+                        s.setStoreVersion(counter.incrementAndGet());
                         s.store();
                     }
                 }
             };
             task.execute();
+            while (counter.get() < 5) {
                 Thread.sleep(1);
+            }
             try {
                 s.close();
                 // sometimes closing works, in which case
-            // storing fails at some point
-            Thread.sleep(100);
+                // storing must fail at some point (not necessarily
+                // immediately)
+                for (int x = counter.get(), y = x; x <= y + 2; x++) {
+                    Thread.sleep(1);
+                }
                 Exception e = task.getException();
                 assertEquals(DataUtils.ERROR_CLOSED,
                         DataUtils.getErrorCode(e.getMessage()));
             } catch (IllegalStateException e) {
                 // sometimes storing works, in which case
-            // closing fails
+                // closing must fail
                 assertEquals(DataUtils.ERROR_WRITING_FAILED,
                         DataUtils.getErrorCode(e.getMessage()));
                 task.get();
             }
             s.close();
         }
+    }
 
     /**
      * Test the concurrent map implementation.
@@ -177,7 +266,7 @@ public class TestConcurrent extends TestMVStore {
             @Override
             public void call() throws Exception {
                 while (!stop) {
-                    for (int i = 0; i < 20; i++) {
+                    for (int i = 0; i < 10; i++) {
                         map.put(i, new byte[100 * r.nextInt(100)]);
                     }
                     s.store();
@@ -187,7 +276,7 @@ public class TestConcurrent extends TestMVStore {
                     if (len > 1024 * 1024) {
                         // slow down writing a lot
                         Thread.sleep(200);
-                    } else if (len > 1024 * 100) {
+                    } else if (len > 20 * 1024) {
                         // slow down writing
                         Thread.sleep(20);
                     }

h2/src/test/org/h2/test/store/TestMVStore.java

@@ -547,6 +547,7 @@ public class TestMVStore extends TestBase {
         MVMap<Integer, String> map;
         s = new MVStore.Builder().
                 fileName(fileName).
+                writeDelay(-1).
                 compressData().open();
         map = s.openMap("test");
         // add 10 MB of data
@@ -556,7 +557,7 @@ public class TestMVStore extends TestBase {
         s.store();
         s.close();
         int[] expectedReadsForCacheSize = {
-                3405, 2590, 1924, 1440, 1108, 956, 918
+                3405, 2590, 1924, 1440, 1103, 956, 918
         };
         for (int cacheSize = 0; cacheSize <= 6; cacheSize += 4) {
             s = new MVStore.Builder().