[GitHub] [airflow] kazanzhy commented on a change in pull request #21307: Fixed error in PostgresToGCSOperator on the empty resultset

[GitBox <gi...@apache.org>]

kazanzhy commented on a change in pull request #21307:
URL: https://github.com/apache/airflow/pull/21307#discussion_r798974645



##########
File path: airflow/providers/google/cloud/transfers/postgres_to_gcs.py
##########
@@ -41,26 +41,22 @@ class _PostgresServerSideCursorDecorator:
 
     def __init__(self, cursor):
         self.cursor = cursor
-        self.rows = []
         self.initialized = False
 
     def __iter__(self):
         return self
 
     def __next__(self):
-        if self.rows:
-            return self.rows.pop()
-        else:
-            self.initialized = True
-            return next(self.cursor)
+        self.initialized = True
+        return next(self.cursor)
 
     @property
     def description(self):
         """Fetch first row to initialize cursor description when using server side cursor."""
         if not self.initialized:
-            element = self.cursor.fetchone()
-            self.rows.append(element)
             self.initialized = True
+            self.cursor.fetchone()
+            self.cursor.scroll(0, mode='absolute')

Review comment:
       If `.scroll(-1)` is more clear then I change




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