Add functions to do a manual flush of the db session and call flush before change to READ_ONLY mode to be sure we index the current object

dspace-api/src/main/java/org/dspace/core/Context.java

@@ -880,6 +880,16 @@ public class Context implements AutoCloseable {
         dbConnection.uncacheEntity(entity);
     }
 
+    /**
+     * Flush the current Session to synchronizes the in-memory state of the Session
+     * with the database (write changes to the database)
+     *
+     * @throws SQLException passed through.
+     */
+    public void flushDBChanges() throws SQLException {
+        dbConnection.flushSession();
+    }
+
     public Boolean getCachedAuthorizationResult(DSpaceObject dspaceObject, int action, EPerson eperson) {
         if (isReadOnly()) {
             return readOnlyCache.getCachedAuthorizationResult(dspaceObject, action, eperson);

dspace-api/src/main/java/org/dspace/core/DBConnection.java

@@ -148,4 +148,12 @@ public interface DBConnection<T> {
      * @throws java.sql.SQLException passed through.
      */
     public <E extends ReloadableEntity> void uncacheEntity(E entity) throws SQLException;
+
+    /**
+     * Do a manual flush. This synchronizes the in-memory state of the Session
+     * with the database (write changes to the database)
+     *
+     * @throws SQLException passed through.
+     */
+    public void flushSession() throws SQLException;
 }

dspace-api/src/main/java/org/dspace/core/HibernateDBConnection.java

@@ -337,4 +337,17 @@ public class HibernateDBConnection implements DBConnection<Session> {
             }
         }
     }
+
+    /**
+     * Do a manual flush. This synchronizes the in-memory state of the Session
+     * with the database (write changes to the database)
+     *
+     * @throws SQLException passed through.
+     */
+    @Override
+    public void flushSession() throws SQLException {
+        if (getSession().isDirty()) {
+            getSession().flush();
+        }
+    }
 }

dspace-api/src/main/java/org/dspace/discovery/IndexEventConsumer.java

@@ -201,7 +201,11 @@ public class IndexEventConsumer implements Consumer {
     @Override
     public void end(Context ctx) throws Exception {
 
-        // Change the mode to readonly to improve the performance
+        // Change the mode to readonly to improve performance
+        // First, we flush the changes to database, if session is dirty, has pending changes
+        // to synchronize with database, without this flush it could index an old version of
+        // the object
+        ctx.flushDBChanges();
         Context.Mode originalMode = ctx.getCurrentMode();
         ctx.setMode(Context.Mode.READ_ONLY);
 
@@ -234,9 +238,9 @@ public class IndexEventConsumer implements Consumer {
                 uniqueIdsToDelete.clear();
                 createdItemsToUpdate.clear();
             }
-        }
 
-        ctx.setMode(originalMode);
+            ctx.setMode(originalMode);
+        }
     }
 
     private void indexObject(Context ctx, IndexableObject iu, boolean preDb) throws SQLException {