Only attempt to flush if cancelled

server/block_processor.py

@@ -382,8 +382,9 @@ class BlockProcessor(server.db.DB):
             while True:
                 await self._wait_for_update()
                 await asyncio.sleep(0)   # Yield
-        finally:
+        except asyncio.CancelledError:
             self.flush(True)
+            raise
 
     async def _wait_for_update(self):
         '''Wait for the prefetcher to deliver blocks or a mempool update.

server/db.py

@@ -119,7 +119,6 @@ class DB(LoggedClass):
 
         if tx_height > self.db_height:
             return None, tx_height
-            raise self.DBError('tx_num {:,d} is not on disk')
 
         file_pos = tx_num * 32
         file_num, offset = divmod(file_pos, self.tx_hash_file_size)