MVStore: make fields final, streamline constructor code

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

@@ -26,6 +26,7 @@ import org.h2.mvstore.cache.CacheLongKeyLIRS;
 import org.h2.mvstore.type.StringDataType;
 import org.h2.util.MathUtils;
 import org.h2.util.New;
+import org.h2.util.Utils;
 
 /*
 
@@ -151,8 +152,8 @@ public final class MVStore {
 
     private volatile boolean closed;
 
-    private FileStore fileStore;
-    private boolean fileStoreIsProvided;
+    private final FileStore fileStore;
+    private final boolean fileStoreIsProvided;
 
     private final int pageSplitSize;
 
@@ -161,14 +162,14 @@ public final class MVStore {
      * It is split in 16 segments. The stack move distance is 2% of the expected
      * number of entries.
      */
-    private CacheLongKeyLIRS<Page> cache;
+    private final CacheLongKeyLIRS<Page> cache;
 
     /**
      * The page chunk references cache. The default size is 4 MB, and the
      * average size is 2 KB. It is split in 16 segments. The stack move distance
      * is 2% of the expected number of entries.
      */
-    private CacheLongKeyLIRS<PageChildren> cacheChunkRef;
+    private final CacheLongKeyLIRS<PageChildren> cacheChunkRef;
 
     /**
      * The newest chunk. If nothing was stored yet, this field is not set.
@@ -198,12 +199,12 @@ public final class MVStore {
      * The metadata map. Write access to this map needs to be synchronized on
      * the store.
      */
-    private MVMap<String, String> meta;
+    private final MVMap<String, String> meta;
 
     private final ConcurrentHashMap<Integer, MVMap<?, ?>> maps =
             new ConcurrentHashMap<>();
 
-    private HashMap<String, Object> storeHeader = New.hashMap();
+    private final HashMap<String, Object> storeHeader = New.hashMap();
 
     private WriteBuffer writeBuffer;
 
@@ -221,7 +222,7 @@ public final class MVStore {
 
     private Compressor compressorHigh;
 
-    private final UncaughtExceptionHandler backgroundExceptionHandler;
+    public final UncaughtExceptionHandler backgroundExceptionHandler;
 
     private volatile long currentVersion;
 
@@ -292,67 +293,64 @@ public final class MVStore {
      *             occurred while opening
      * @throws IllegalArgumentException if the directory does not exist
      */
-    MVStore(HashMap<String, Object> config) {
-        Object o = config.get("compress");
-        this.compressionLevel = o == null ? 0 : (Integer) o;
+    MVStore(Map<String, Object> config) {
+        this.compressionLevel = Utils.getConfigParam(config, "compress", 0);
         String fileName = (String) config.get("fileName");
-        fileStore = (FileStore) config.get("fileStore");
+        FileStore fileStore = (FileStore) config.get("fileStore");
         fileStoreIsProvided = fileStore != null;
         if(fileStore == null && fileName != null) {
             fileStore = new FileStore();
         }
-        o = config.get("pageSplitSize");
-        int pgSplitSize;
+        this.fileStore = fileStore;
+
+        CacheLongKeyLIRS.Config cc = null;
+        if (this.fileStore != null) {
+            int mb = Utils.getConfigParam(config, "cacheSize", 16);
+            if (mb > 0) {
+                cc = new CacheLongKeyLIRS.Config();
+                cc.maxMemory = mb * 1024L * 1024L;
+                Object o = config.get("cacheConcurrency");
                 if (o != null) {
-            pgSplitSize = (Integer) o;
-        } else if(fileStore != null) {
-            pgSplitSize = 16 * 1024;
+                    cc.segmentCount = (Integer)o;
+                }
+            }
+        }
+        if (cc != null) {
+            cache = new CacheLongKeyLIRS<>(cc);
+            cc.maxMemory /= 4;
+            cacheChunkRef = new CacheLongKeyLIRS<>(cc);
         } else {
-            pgSplitSize = 48; // number of keys per page in that case
+            cache = null;
+            cacheChunkRef = null;
+        }
+
+        int pgSplitSize = Utils.getConfigParam(config, "pageSplitSize", 16 * 1024);
+        // Make sure pages will fit into cache
+        if (cache != null && pgSplitSize > cache.getMaxItemSize()) {
+            pgSplitSize = (int)cache.getMaxItemSize();
         }
         pageSplitSize = pgSplitSize;
-        o = config.get("backgroundExceptionHandler");
-        this.backgroundExceptionHandler = (UncaughtExceptionHandler) o;
+        backgroundExceptionHandler =
+                (UncaughtExceptionHandler)config.get("backgroundExceptionHandler");
         meta = new MVMap<>(StringDataType.INSTANCE,
                 StringDataType.INSTANCE);
         HashMap<String, Object> c = New.hashMap();
         c.put("id", 0);
         c.put("createVersion", currentVersion);
         meta.init(this, c);
-        if (fileStore == null) {
-            cache = null;
-            cacheChunkRef = null;
-            return;
-        }
-        retentionTime = fileStore.getDefaultRetentionTime();
-        boolean readOnly = config.containsKey("readOnly");
-        o = config.get("cacheSize");
-        int mb = o == null ? 16 : (Integer) o;
-        if (mb > 0) {
-            CacheLongKeyLIRS.Config cc = new CacheLongKeyLIRS.Config();
-            cc.maxMemory = mb * 1024L * 1024L;
-            o = config.get("cacheConcurrency");
-            if (o != null) {
-                cc.segmentCount = (Integer) o;
-            }
-            cache = new CacheLongKeyLIRS<>(cc);
-            cc.maxMemory /= 4;
-            cacheChunkRef = new CacheLongKeyLIRS<>(cc);
-        }
-        o = config.get("autoCommitBufferSize");
-        int kb = o == null ? 1024 : (Integer) o;
+        if (this.fileStore != null) {
+            retentionTime = this.fileStore.getDefaultRetentionTime();
+            int kb = Utils.getConfigParam(config, "autoCommitBufferSize", 1024);
             // 19 KB memory is about 1 KB storage
             autoCommitMemory = kb * 1024 * 19;
-
-        o = config.get("autoCompactFillRate");
-        autoCompactFillRate = o == null ? 50 : (Integer) o;
-
+            autoCompactFillRate = Utils.getConfigParam(config, "autoCompactFillRate", 50);
             char[] encryptionKey = (char[]) config.get("encryptionKey");
             try {
                 if (!fileStoreIsProvided) {
-                fileStore.open(fileName, readOnly, encryptionKey);
+                    boolean readOnly = config.containsKey("readOnly");
+                    this.fileStore.open(fileName, readOnly, encryptionKey);
                 }
-            if (fileStore.size() == 0) {
+                if (this.fileStore.size() == 0) {
                     creationTime = getTimeAbsolute();
                     lastCommitTime = creationTime;
                     storeHeader.put("H", 2);
@@ -374,10 +372,10 @@ public final class MVStore {
 
             // setAutoCommitDelay starts the thread, but only if
             // the parameter is different from the old value
-        o = config.get("autoCommitDelay");
-        int delay = o == null ? 1000 : (Integer) o;
+            int delay = Utils.getConfigParam(config, "autoCommitDelay", 1000);
             setAutoCommitDelay(delay);
         }
+    }
 
     private void panic(IllegalStateException e) {
         if (backgroundExceptionHandler != null) {
@@ -892,30 +890,27 @@ public final class MVStore {
         // the thread also synchronized on this, which
         // could result in a deadlock
         stopBackgroundThread();
-        closed = true;
         synchronized (this) {
+            closed = true;
             if (fileStore != null && shrinkIfPossible) {
                 shrinkFileIfPossible(0);
             }
             // release memory early - this is important when called
             // because of out of memory
-            cache = null;
-            cacheChunkRef = null;
+            if (cache != null) {
+                cache.clear();
+            }
+            if (cacheChunkRef != null) {
+                cacheChunkRef.clear();
+            }
             for (MVMap<?, ?> m : New.arrayList(maps.values())) {
                 m.close();
             }
-            meta = null;
             chunks.clear();
             maps.clear();
-            if (fileStore != null) {
-                try {
-                    if (!fileStoreIsProvided) {
+            if (fileStore != null && !fileStoreIsProvided) {
                 fileStore.close();
             }
-                } finally {
-                    fileStore = null;
-                }
-            }
         }
     }
 

h2/src/main/org/h2/mvstore/cache/CacheLongKeyLIRS.java

@@ -82,13 +82,21 @@ public class CacheLongKeyLIRS<V> {
      * Remove all entries.
      */
     public void clear() {
-        long max = Math.max(1, maxMemory / segmentCount);
+        long max = getMaxItemSize();
         for (int i = 0; i < segmentCount; i++) {
             segments[i] = new Segment<>(
                     max, stackMoveDistance, 8, nonResidentQueueSize);
         }
     }
 
+    /**
+     * Determines max size of the data item size to fit into cache
+     * @return data items size limit
+     */
+    public long getMaxItemSize() {
+        return Math.max(1, maxMemory / segmentCount);
+    }
+
     private Entry<V> find(long key) {
         int hash = getHash(key);
         return getSegment(hash).find(key, hash);

h2/src/main/org/h2/util/Utils.java

@@ -17,6 +17,7 @@ import java.lang.reflect.Modifier;
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.HashMap;
+import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
@@ -75,7 +76,7 @@ public class Utils {
         buff[pos++] = (byte) (x >> 24);
         buff[pos++] = (byte) (x >> 16);
         buff[pos++] = (byte) (x >> 8);
-        buff[pos++] = (byte) x;
+        buff[pos]   = (byte) x;
     }
 
     /**
@@ -722,7 +723,7 @@ public class Utils {
         String s = getProperty(key, null);
         if (s != null) {
             try {
-                return Integer.decode(s).intValue();
+                return Integer.decode(s);
             } catch (NumberFormatException e) {
                 // ignore
             }
@@ -750,6 +751,20 @@ public class Utils {
         return defaultValue;
     }
 
+    public static int getConfigParam(Map<String,?> config, String key, int defaultValue) {
+        Object o = config.get(key);
+        if (o instanceof Number) {
+            return ((Number) o).intValue();
+        } else if (o != null) {
+            try {
+                return Integer.decode(o.toString());
+            } catch (NumberFormatException e) {
+                // ignore
+            }
+        }
+        return defaultValue;
+    }
+
     /**
      * Scale the value with the available memory. If 1 GB of RAM is available,
      * the value is returned, if 2 GB are available, then twice the value, and