From e82722b4eeb264f4576ea4e162564de283de141f Mon Sep 17 00:00:00 2001
From: larkee <larkee@users.noreply.github.com>
Date: Thu, 2 Dec 2021 13:23:59 +1100
Subject: [PATCH 1/2] fix: generate correct max limit when unspecified with
 offset

---
 .../sqlalchemy_spanner/sqlalchemy_spanner.py  |  3 ++-
 test/test_suite.py                            | 25 +++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py b/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
index c38a9b8f..d0af218b 100644
--- a/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
+++ b/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
@@ -259,7 +259,8 @@ def limit_clause(self, select, **kw):
             text += "\n LIMIT " + self.process(select._limit_clause, **kw)
         if select._offset_clause is not None:
             if select._limit_clause is None:
-                text += "\n LIMIT 9223372036854775805"
+                offset = int(self.process(select._offset_clause, **kw))
+                text += f"\n LIMIT {9223372036854775807-offset}"
             text += " OFFSET " + self.process(select._offset_clause, **kw)
         return text
 
diff --git a/test/test_suite.py b/test/test_suite.py
index 0bc4030c..5b56360c 100644
--- a/test/test_suite.py
+++ b/test/test_suite.py
@@ -1616,6 +1616,31 @@ def test_staleness(self):
             assert connection.connection.staleness is None
 
 
+class LimitOffsetTest(fixtures.TestBase):
+    """
+    Check that SQL with an offset and no limit is being generated correctly.
+    """
+
+    def setUp(self):
+        self._engine = create_engine(get_db_url(), pool_size=1)
+        self._metadata = MetaData(bind=self._engine)
+
+        self._table = Table(
+            "users",
+            self._metadata,
+            Column("user_id", Integer, primary_key=True),
+            Column("user_name", String(16), nullable=False),
+        )
+
+        self._metadata.create_all(self._engine)
+
+    def test_offset_only(self):
+        for offset in [1, 7, 10, 100, 1000, 10000]:
+
+            with self._engine.connect().execution_options(read_only=True) as connection:
+                list(connection.execute(self._table.select().offset(offset)).fetchall())
+
+
 class ComputedReflectionFixtureTest(_ComputedReflectionFixtureTest):
     @classmethod
     def define_tables(cls, metadata):

From ffd79979b60adde69d15ad61e5740c25cf73e0ce Mon Sep 17 00:00:00 2001
From: larkee <larkee@users.noreply.github.com>
Date: Thu, 2 Dec 2021 14:29:52 +1100
Subject: [PATCH 2/2] fix: use _offset

---
 google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py b/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
index d0af218b..e28ac86d 100644
--- a/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
+++ b/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
@@ -259,8 +259,7 @@ def limit_clause(self, select, **kw):
             text += "\n LIMIT " + self.process(select._limit_clause, **kw)
         if select._offset_clause is not None:
             if select._limit_clause is None:
-                offset = int(self.process(select._offset_clause, **kw))
-                text += f"\n LIMIT {9223372036854775807-offset}"
+                text += f"\n LIMIT {9223372036854775807-select._offset}"
             text += " OFFSET " + self.process(select._offset_clause, **kw)
         return text