diff --git a/txpool/pool.go b/txpool/pool.go
index 5b8427bc2..360b51e0d 100644
--- a/txpool/pool.go
+++ b/txpool/pool.go
@@ -572,13 +572,15 @@ func (sc *SendersCache) flush(tx kv.RwTx, byNonce *ByNonce) error {
 		if byNonce.count(binary.BigEndian.Uint64(id)) > 0 {
 			return nil
 		}
-		tx.ForEach(kv.PooledTransaction, nil, func(k, v []byte) error {
-			senderID := binary.BigEndian.Uint64(v[:8])
-			if senderID == binary.BigEndian.Uint64(id) {
-				panic("why?")
-			}
-			return nil
-		})
+		if ASSERT {
+			tx.ForEach(kv.PooledTransaction, nil, func(k, v []byte) error {
+				senderID := binary.BigEndian.Uint64(v[:8])
+				if senderID == binary.BigEndian.Uint64(id) {
+					panic("why?")
+				}
+				return nil
+			})
+		}
 		if err := tx.Delete(kv.PooledSenderID, addr, nil); err != nil {
 			return err
 		}
@@ -589,17 +591,19 @@ func (sc *SendersCache) flush(tx kv.RwTx, byNonce *ByNonce) error {
 			return err
 		}
 
-		tx.ForEach(kv.PooledTransaction, nil, func(k, v []byte) error {
-			vv, err := tx.GetOne(kv.PooledSenderIDToAdress, v[:8])
-			if err != nil {
-				return err
-			}
-			if len(vv) == 0 {
-				fmt.Printf("no: %x,%x\n", id, addr)
-				panic("no-no")
-			}
-			return nil
-		})
+		if ASSERT {
+			tx.ForEach(kv.PooledTransaction, nil, func(k, v []byte) error {
+				vv, err := tx.GetOne(kv.PooledSenderIDToAdress, v[:8])
+				if err != nil {
+					return err
+				}
+				if len(vv) == 0 {
+					fmt.Printf("no: %x,%x\n", id, addr)
+					panic("no-no")
+				}
+				return nil
+			})
+		}
 		i++
 		return nil
 	}); err != nil {