fix UT and perfect

Signed-off-by: Weihao Li <18110526956@163.com>

Author: Wei-hao-Li

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/memory/NotThreadSafeMemoryReservationManager.java

@@ -28,6 +28,8 @@
 
 import javax.annotation.concurrent.NotThreadSafe;
 
+import static com.google.common.base.Preconditions.checkState;
+
 @NotThreadSafe
 public class NotThreadSafeMemoryReservationManager implements MemoryReservationManager {
   // To avoid reserving memory too frequently, we choose to do it in batches. This is the lower
@@ -151,23 +153,20 @@ private long deductReleaseAccounting(final long size) {
     remaining -= fallbackBytesInTotal;
     fallbackBytesInTotal = 0;
 
-    long poolBytes = Math.min(remaining, reservedBytesInTotal);
-    reservedBytesInTotal -= poolBytes;
-    return poolBytes;
+    reservedBytesInTotal -= remaining;
+    checkState(reservedBytesInTotal >= 0, "Released bytes has been larger than reserved!");
+    return remaining;
   }
 
   @Override
   public void releaseAllReservedMemory() {
-    if (bytesToBeReleased != 0) {
-      releaseBytesImmediately(bytesToBeReleased);
-      bytesToBeReleased = 0;
-    }
-    if (reservedBytesInTotal > 0) {
+    if (reservedBytesInTotal != 0) {
       LOCAL_EXECUTION_PLANNER.releaseToFreeMemoryForOperators(reservedBytesInTotal);
+      reservedBytesInTotal = 0;
     }
-    reservedBytesInTotal = 0;
     fallbackBytesInTotal = 0;
     bytesToBeReserved = 0;
+    bytesToBeReleased = 0;
   }
 
   @Override

iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/execution/operator/CteScanOperatorTest.java

@@ -177,7 +177,7 @@ public void testMultipleCteScanOperators() throws Exception {
         new CteScanOperator(operatorContext, planNodeId, cteDataStore, queryId);
     assertEquals(2, cteDataStore.getCount());
 
-    assertEquals(896, cteDataStore.ramBytesUsed());
+    assertEquals(904, cteDataStore.ramBytesUsed());
 
     // Both operators should be able to read data
     assertTrue(operator1.hasNext());