LSS logging happens in the monitor

community/kernel/src/main/java/org/neo4j/kernel/api/labelscan/LabelScanStore.java

@@ -37,49 +37,32 @@ public interface LabelScanStore extends Lifecycle
     interface Monitor
     {
         Monitor EMPTY = new Monitor()
-        {
-            @Override
-            public void init()
-            {
-            }
-
-            @Override
-            public void noIndex()
-            {
-            }
-
-            @Override
-            public void lockedIndex( Exception e )
-            {
-            }
-
-            @Override
-            public void notValidIndex()
-            {
-            }
-
-            @Override
-            public void rebuilding()
-            {
-            }
-
-            @Override
-            public void rebuilt( long roughNodeCount )
-            {
-            }
+        {   // empty
         };
 
-        void init();
+        default void init()
+        {   // empty
+        }
 
-        void noIndex();
+        default void noIndex()
+        {   // empty
+        }
 
-        void lockedIndex( Exception e );
+        default void lockedIndex( Exception e )
+        {   // empty
+        }
 
-        void notValidIndex();
+        default void notValidIndex()
+        {   // empty
+        }
 
-        void rebuilding();
+        default void rebuilding()
+        {   // empty
+        }
 
-        void rebuilt( long roughNodeCount );
+        default void rebuilt( long roughNodeCount )
+        {   // empty
+        }
     }
 
     /**

community/kernel/src/main/java/org/neo4j/kernel/api/labelscan/LoggingMonitor.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2002-2017 "Neo Technology,"
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.kernel.api.labelscan;
+
+import org.neo4j.kernel.api.labelscan.LabelScanStore.Monitor;
+import org.neo4j.logging.Log;
+
+/**
+ * Logs about important events about {@link LabelScanStore} {@link Monitor}.
+ */
+public class LoggingMonitor implements Monitor
+{
+    private final Log log;
+    private final Monitor delegate;
+
+    public LoggingMonitor( Log log )
+    {
+        this( log, Monitor.EMPTY );
+    }
+
+    public LoggingMonitor( Log log, Monitor delegate )
+    {
+        this.log = log;
+        this.delegate = delegate;
+    }
+
+    @Override
+    public void init()
+    {
+        delegate.init();
+    }
+
+    @Override
+    public void noIndex()
+    {
+        log.info( "No scan store found, this might just be first use. Preparing to rebuild." );
+        delegate.noIndex();
+    }
+
+    @Override
+    public void lockedIndex( Exception e )
+    {
+        log.error( "Scan store is locked by another process or database", e );
+        delegate.lockedIndex( e );
+    }
+
+    @Override
+    public void notValidIndex()
+    {
+        log.warn( "Scan store could not be read. Preparing to rebuild." );
+        delegate.notValidIndex();
+    }
+
+    @Override
+    public void rebuilding()
+    {
+        log.info( "Rebuilding scan store, this may take a while" );
+        delegate.rebuilding();
+    }
+
+    @Override
+    public void rebuilt( long roughNodeCount )
+    {
+        log.info( "Scan store rebuilt (roughly " + roughNodeCount + " nodes)" );
+        delegate.rebuilt( roughNodeCount );
+    }
+}

community/kernel/src/main/java/org/neo4j/kernel/impl/api/scan/NativeLabelScanStoreExtension.java

@@ -23,13 +23,17 @@
 
 import org.neo4j.graphdb.factory.GraphDatabaseSettings;
 import org.neo4j.io.pagecache.PageCache;
+import org.neo4j.kernel.api.labelscan.LoggingMonitor;
 import org.neo4j.kernel.api.labelscan.LabelScanStore;
+import org.neo4j.kernel.api.labelscan.LabelScanStore.Monitor;
 import org.neo4j.kernel.configuration.Config;
 import org.neo4j.kernel.extension.KernelExtensionFactory;
 import org.neo4j.kernel.impl.api.index.IndexStoreView;
 import org.neo4j.kernel.impl.index.labelscan.NativeLabelScanStore;
+import org.neo4j.kernel.impl.logging.LogService;
 import org.neo4j.kernel.impl.spi.KernelContext;
 import org.neo4j.kernel.lifecycle.Lifecycle;
+import org.neo4j.logging.Log;
 
 public class NativeLabelScanStoreExtension extends
         KernelExtensionFactory<NativeLabelScanStoreExtension.Dependencies>
@@ -45,6 +49,8 @@ public interface Dependencies
         PageCache pageCache();
 
         Supplier<IndexStoreView> indexStoreView();
+
+        LogService getLogService();
     }
 
     public NativeLabelScanStoreExtension()
@@ -62,6 +68,8 @@ public NativeLabelScanStoreExtension( int priority, LabelScanStore.Monitor monit
     @Override
     public Lifecycle newInstance( KernelContext context, Dependencies dependencies ) throws Throwable
     {
+        Log log = dependencies.getLogService().getInternalLog( NativeLabelScanStore.class );
+        Monitor monitor = new LoggingMonitor( log, this.monitor );
         NativeLabelScanStore labelScanStore = new NativeLabelScanStore(
                 dependencies.pageCache(),
                 context.storeDir(),

community/kernel/src/main/java/org/neo4j/kernel/impl/index/labelscan/NativeLabelScanStore.java

@@ -24,7 +24,7 @@
 import java.io.UncheckedIOException;
 import java.nio.file.NoSuchFileException;
 import java.util.function.IntFunction;
-import java.util.stream.Stream;
+import java.util.stream.Collectors;
 
 import org.neo4j.cursor.RawCursor;
 import org.neo4j.graphdb.ResourceIterator;
@@ -43,6 +43,7 @@
 import org.neo4j.kernel.impl.store.UnderlyingStorageException;
 import org.neo4j.storageengine.api.schema.LabelScanReader;
 
+import static org.neo4j.helpers.collection.Iterables.single;
 import static org.neo4j.helpers.collection.Iterators.asResourceIterator;
 import static org.neo4j.helpers.collection.Iterators.iterator;
 import static org.neo4j.kernel.impl.store.MetaDataStore.DEFAULT_NAME;
@@ -73,8 +74,15 @@ public class NativeLabelScanStore implements LabelScanStore
 {
     static final String FILE_NAME = DEFAULT_NAME + ".labelscanstore.db";
 
+    /**
+     * Whether or not this label scan store is read-only.
+     */
     private final boolean readOnly;
-    private final NativeLabelScanStoreMonitor monitor;
+
+    /**
+     * Monitoring internal events.
+     */
+    private final Monitor monitor;
 
     /**
      * {@link PageCache} to {@link PageCache#map(File, int, java.nio.file.OpenOption...)}
@@ -117,6 +125,10 @@ public class NativeLabelScanStore implements LabelScanStore
      */
     private boolean recoveryStarted;
 
+    /**
+     * Set during {@link #init()} if {@link #start()} will need to rebuild the whole label scan store from
+     * {@link FullStoreChangeStream}.
+     */
     private boolean needsRebuild;
 
     private final NativeLabelScanWriter singleWriter;
@@ -139,7 +151,7 @@ public NativeLabelScanStore( PageCache pageCache, File storeDir,
         this.storeFile = new File( storeDir, FILE_NAME );
         this.singleWriter = new NativeLabelScanWriter( 1_000 );
         this.readOnly = readOnly;
-        this.monitor = new NativeLabelScanStoreMonitor( monitor );
+        this.monitor = monitor;
     }
 
     /**
@@ -209,12 +221,6 @@ public void force( IOLimiter limiter ) throws UnderlyingStorageException
         }
     }
 
-    /**
-     * Unsupported by this implementation.
-     *
-     * @return nothing since {@link UnsupportedOperationException} will be thrown.
-     * @throws UnsupportedOperationException since not supported by this implementation.
-     */
     @Override
     public AllEntriesLabelScanReader allNodeLabelRanges()
     {
@@ -278,16 +284,20 @@ public void init() throws IOException
 
         try
         {
-            create( monitor );
             needsRebuild = !storeExists;
+            if ( !storeExists )
+            {
+                monitor.noIndex();
+            }
+
+            instantiateTree();
         }
         catch ( MetadataMismatchException e )
         {
             // GBPTree is corrupt. Try to rebuild.
-            // todo log
             monitor.notValidIndex();
             drop();
-            create( GBPTree.NO_MONITOR );
+            instantiateTree();
             needsRebuild = true;
         }
     }
@@ -296,28 +306,28 @@ private boolean storeExists() throws IOException
     {
         try
         {
-            Stream<FileHandle> stream = pageCache.streamFilesRecursive( storeFile );
-            long count = stream.count();
-            if ( count > 1 )
-            {
-                throw new IllegalStateException( "Multiple " + storeFile + " existed" );
-            }
-            return count == 1;
+            storeFileHandle();
+            return true;
         }
         catch ( NoSuchFileException e )
         {
             return false;
         }
     }
 
-    private void create( GBPTree.Monitor monitor ) throws IOException
+    private FileHandle storeFileHandle() throws IOException
+    {
+        return single( pageCache.streamFilesRecursive( storeFile ).collect( Collectors.toList() ) );
+    }
+
+    private void instantiateTree() throws IOException
     {
-        index = new GBPTree<>( pageCache, storeFile, new LabelScanLayout(), pageSize, monitor );
+        index = new GBPTree<>( pageCache, storeFile, new LabelScanLayout(), pageSize, GBPTree.NO_MONITOR );
     }
 
     private void drop() throws IOException
     {
-        storeFile.delete();
+        storeFileHandle().delete();
     }
 
     /**
@@ -336,10 +346,8 @@ public void start() throws IOException
                 throw new IOException( "Tried to start label scan store " + storeFile +
                         " as read-only and the index needs rebuild. This makes the label scan store unusable" );
             }
-            // todo log
             monitor.rebuilding();
             long numberOfNodes = LabelScanStoreProvider.rebuild( this, fullStoreChangeStream );
-            // todo log
             monitor.rebuilt( numberOfNodes );
             needsRebuild = false;
         }
@@ -372,57 +380,4 @@ public void shutdown() throws IOException
     {
         index.close();
     }
-
-    // todo make this guy log the stuffs
-    private class NativeLabelScanStoreMonitor implements Monitor, GBPTree.Monitor
-    {
-        private final Monitor delegate;
-
-        NativeLabelScanStoreMonitor( Monitor delegate )
-        {
-            this.delegate = delegate;
-        }
-
-        @Override
-        public void init()
-        {
-            delegate.init();
-        }
-
-        @Override
-        public void noIndex()
-        {
-            delegate.noIndex();
-        }
-
-        @Override
-        public void lockedIndex( Exception e )
-        {
-            delegate.lockedIndex( e );
-        }
-
-        @Override
-        public void notValidIndex()
-        {
-            delegate.notValidIndex();
-        }
-
-        @Override
-        public void rebuilding()
-        {
-            delegate.rebuilding();
-        }
-
-        @Override
-        public void rebuilt( long roughNodeCount )
-        {
-            delegate.rebuilt( roughNodeCount );
-        }
-
-        @Override
-        public void noStoreFile()
-        {
-            noIndex();
-        }
-    }
 }