Change from dataSize to long to avoid unnecessary creation

Author: shangm2

presto-main/src/main/java/com/facebook/presto/dispatcher/FailedDispatchQuery.java

@@ -23,7 +23,6 @@
 import com.facebook.presto.spi.resourceGroups.ResourceGroupId;
 import com.facebook.presto.spi.resourceGroups.ResourceGroupQueryLimits;
 import com.google.common.util.concurrent.ListenableFuture;
-import io.airlift.units.DataSize;
 import io.airlift.units.Duration;
 import org.joda.time.DateTime;
 
@@ -34,7 +33,6 @@
 import static com.facebook.presto.execution.QueryState.FAILED;
 import static com.facebook.presto.server.BasicQueryInfo.immediateFailureQueryInfo;
 import static com.google.common.util.concurrent.Futures.immediateFuture;
-import static io.airlift.units.DataSize.Unit.BYTE;
 import static java.util.Objects.requireNonNull;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
@@ -178,15 +176,15 @@ public Duration getTotalCpuTime()
     }
 
     @Override
-    public DataSize getTotalMemoryReservation()
+    public long getTotalMemoryReservationInBytes()
     {
-        return new DataSize(0, BYTE);
+        return 0L;
     }
 
     @Override
-    public DataSize getUserMemoryReservation()
+    public long getUserMemoryReservationInBytes()
     {
-        return new DataSize(0, BYTE);
+        return 0L;
     }
 
     @Override

presto-main/src/main/java/com/facebook/presto/dispatcher/LocalDispatchQuery.java

@@ -34,7 +34,6 @@
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.SettableFuture;
-import io.airlift.units.DataSize;
 import io.airlift.units.Duration;
 import org.joda.time.DateTime;
 
@@ -53,7 +52,6 @@
 import static com.facebook.presto.spi.StandardErrorCode.USER_CANCELED;
 import static com.facebook.presto.util.Failures.toFailure;
 import static com.google.common.util.concurrent.Futures.nonCancellationPropagating;
-import static io.airlift.units.DataSize.Unit.BYTE;
 import static java.util.Objects.requireNonNull;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
@@ -303,19 +301,19 @@ public Duration getTotalCpuTime()
     }
 
     @Override
-    public DataSize getTotalMemoryReservation()
+    public long getTotalMemoryReservationInBytes()
     {
         return tryGetQueryExecution()
-                .map(QueryExecution::getTotalMemoryReservation)
-                .orElseGet(() -> new DataSize(0, BYTE));
+                .map(QueryExecution::getTotalMemoryReservationInBytes)
+                .orElse(0L);
     }
 
     @Override
-    public DataSize getUserMemoryReservation()
+    public long getUserMemoryReservationInBytes()
     {
         return tryGetQueryExecution()
-                .map(QueryExecution::getUserMemoryReservation)
-                .orElseGet(() -> new DataSize(0, BYTE));
+                .map(QueryExecution::getUserMemoryReservationInBytes)
+                .orElse(0L);
     }
 
     public int getRunningTaskCount()