Added option for index access to fetch ahead to reduce likelihood of deadlocks.

1 files changed, 13 insertions, 1 deletions

diff --git a/src/main/java/com/amazon/carbonado/repo/indexed/IndexedCursor.java b/src/main/java/com/amazon/carbonado/repo/indexed/IndexedCursor.java
index bce6975..04eb478 100644
--- a/src/main/java/com/amazon/carbonado/repo/indexed/IndexedCursor.java
+++ b/src/main/java/com/amazon/carbonado/repo/indexed/IndexedCursor.java
@@ -32,6 +32,7 @@ import com.amazon.carbonado.Storage;
 import com.amazon.carbonado.Transaction;

 

 import com.amazon.carbonado.cursor.AbstractCursor;

+import com.amazon.carbonado.cursor.FetchAheadCursor;

 

 import com.amazon.carbonado.spi.RepairExecutor;

 

@@ -44,6 +45,13 @@ import com.amazon.carbonado.synthetic.SyntheticStorableReferenceAccess;
  * @author Brian S O'Neill

  */

 class IndexedCursor<S extends Storable> extends AbstractCursor<S> {

+    private static final int FETCH_AHEAD;

+

+    static {

+        String prefix = IndexedCursor.class.getName() + '.';

+        FETCH_AHEAD = Integer.getInteger(prefix + "fetchAhead", 0);

+    }

+

     private final Cursor<? extends Storable> mCursor;

     private final IndexedStorage<S> mStorage;

     private final SyntheticStorableReferenceAccess<S> mAccessor;

@@ -52,7 +60,11 @@ class IndexedCursor<S extends Storable> extends AbstractCursor<S> {
 

     IndexedCursor(Cursor<? extends Storable> indexEntryCursor,

                   IndexedStorage<S> storage,

-                  SyntheticStorableReferenceAccess<S> indexAccessor) {

+                  SyntheticStorableReferenceAccess<S> indexAccessor)

+    {

+        if (FETCH_AHEAD > 0) {

+            indexEntryCursor = new FetchAheadCursor(indexEntryCursor, FETCH_AHEAD);

+        }

         mCursor = indexEntryCursor;

         mStorage = storage;

         mAccessor = indexAccessor;