Rename attemp => retry, and add feature toggle

neo4j · Oct 26, 2018 · c0b96f4 · c0b96f4
1 parent 570e0a1
commit c0b96f4
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Showing 2 changed files with 12 additions and 9 deletions.
diff --git a/...unity/kernel/src/main/java/org/neo4j/kernel/impl/store/kvstore/AbstractKeyValueStore.java b/...unity/kernel/src/main/java/org/neo4j/kernel/impl/store/kvstore/AbstractKeyValueStore.java
@@ -35,6 +35,7 @@
 import org.neo4j.kernel.impl.locking.LockWrapper;
 import org.neo4j.kernel.impl.store.UnderlyingStorageException;
 import org.neo4j.kernel.lifecycle.LifecycleAdapter;
+import org.neo4j.util.FeatureToggles;
 
 import static org.neo4j.kernel.impl.locking.LockWrapper.readLock;
 import static org.neo4j.kernel.impl.locking.LockWrapper.writeLock;
@@ -48,6 +49,8 @@
 @State( State.Strategy.CONCURRENT_HASH_MAP )
 public abstract class AbstractKeyValueStore<Key> extends LifecycleAdapter
 {
+    static final long MAX_LOOKUP_RETRY_COUNT = FeatureToggles.getLong( AbstractKeyValueStore.class, "maxLookupRetryCount", 1024 );
+
     private final ReadWriteLock updateLock = new ReentrantReadWriteLock( /*fair=*/true );
     private final Format format;
     final RotationStrategy rotationStrategy;
@@ -92,8 +95,8 @@ public String toString()
     protected final <Value> Value lookup( Key key, Reader<Value> reader ) throws IOException
     {
         ValueLookup<Value> lookup = new ValueLookup<>( reader );
-        int attemptsLeft = 1024;
-        while ( attemptsLeft > 0 )
+        long retriesLeft = MAX_LOOKUP_RETRY_COUNT;
+        while ( retriesLeft > 0 )
         {
             ProgressiveState<Key> originalState = this.state;
             try
@@ -109,9 +112,9 @@ protected final <Value> Value lookup( Key key, Reader<Value> reader ) throws IOE
                     throw e;
                 }
             }
-            attemptsLeft--;
+            retriesLeft--;
         }
-        throw new IOException( String.format( "Failed to lookup `%s` in key value store", key ) );
+        throw new IOException( String.format( "Failed to lookup `%s` in key value store, after %d retries", key, MAX_LOOKUP_RETRY_COUNT ) );
     }
 
     /** Introspective feature, not thread safe. */

diff --git a/community/kernel/src/main/java/org/neo4j/kernel/impl/store/kvstore/KeyValueStoreFile.java b/community/kernel/src/main/java/org/neo4j/kernel/impl/store/kvstore/KeyValueStoreFile.java
@@ -28,6 +28,7 @@
 import org.neo4j.kernel.impl.store.UnderlyingStorageException;
 
 import static org.neo4j.io.pagecache.PagedFile.PF_SHARED_READ_LOCK;
+import static org.neo4j.kernel.impl.store.kvstore.AbstractKeyValueStore.MAX_LOOKUP_RETRY_COUNT;
 import static org.neo4j.kernel.impl.store.kvstore.BigEndianByteArrayBuffer.compare;
 import static org.neo4j.kernel.impl.store.kvstore.BigEndianByteArrayBuffer.newBuffer;
 
@@ -36,7 +37,6 @@
  */
 public class KeyValueStoreFile implements Closeable
 {
-    private static final int ALLOWED_READ_ATTEMPTS = 1024;
     private final PagedFile file;
     private final int keySize;
     private final int valueSize;
@@ -214,29 +214,29 @@ private static boolean visitable( BigEndianByteArrayBuffer key, boolean acceptZe
     static void readKeyValuePair( PageCursor cursor, int offset, WritableBuffer key, WritableBuffer value )
             throws IOException
     {
-        int attemptsLeft = ALLOWED_READ_ATTEMPTS;
+        long retriesLeft = MAX_LOOKUP_RETRY_COUNT;
         do
         {
             cursor.setOffset( offset );
             key.getFrom( cursor );
             value.getFrom( cursor );
         }
-        while ( cursor.shouldRetry() && (--attemptsLeft) > 0 );
+        while ( cursor.shouldRetry() && (--retriesLeft) > 0 );
 
         if ( cursor.checkAndClearBoundsFlag() )
         {
             throwOutOfBounds( cursor, offset );
         }
 
-        if ( attemptsLeft == 0 )
+        if ( retriesLeft == 0 )
         {
             throwFailedRead( cursor, offset );
         }
     }
 
     private static void throwFailedRead( PageCursor cursor, int offset )
     {
-        throwReadError( cursor, offset, "Failed to read after " + ALLOWED_READ_ATTEMPTS + " attempts" );
+        throwReadError( cursor, offset, "Failed to read after " + MAX_LOOKUP_RETRY_COUNT + " retries" );
     }
 
     private static void throwOutOfBounds( PageCursor cursor, int offset )