Fix BEGIN/COMMIT/ROLLBACK silently failing under server cursor mode

web/pgadmin/utils/driver/psycopg3/connection.py

@@ -1173,6 +1173,19 @@ def execute_void(self, query, params=None, formatted_exception_msg=False):
 
         if not status:
             return False, str(cur)
+
+        if isinstance(cur, AsyncDictServerCursor):
+            # A named/server-side cursor's execute() always runs the query
+            # as `DECLARE ... CURSOR FOR <query>`, which cannot express a
+            # transaction-control statement such as BEGIN/COMMIT/ROLLBACK.
+            # Run this one statement through a throwaway plain cursor
+            # instead, leaving the cached server-side cursor untouched, and
+            # treat it as leaving no result set for whatever poll() call
+            # comes next.
+            cur = self.conn.cursor()
+            self.column_info = None
+            self.row_count = 0
+
         query_id = str(secrets.choice(range(1, 9999999)))
 
         current_app.logger.log(

web/pgadmin/utils/driver/psycopg3/tests/test_execute_void_server_cursor.py

@@ -0,0 +1,85 @@
+##########################################################################
+#
+# pgAdmin 4 - PostgreSQL Tools
+#
+# Copyright (C) 2013 - 2026, The pgAdmin Development Team
+# This software is released under the PostgreSQL Licence
+#
+##########################################################################
+
+"""Regression test: ``execute_void()`` must not run a transaction-control
+statement (BEGIN/COMMIT/ROLLBACK) through a cached named/server-side
+cursor.
+
+A named cursor's ``execute()`` always wraps the statement as
+``DECLARE ... CURSOR FOR <query>``, which cannot express BEGIN/COMMIT/
+ROLLBACK. Before the fix, the Commit/Rollback buttons under "server
+cursor" mode silently did nothing: the DECLARE-wrapped call failed
+(actually failing one step earlier, on a ``prepare`` keyword the
+server-side cursor's ``execute()`` doesn't accept at all), the exception
+was swallowed by the background query thread, and the next poll() then
+reported the *previous* query's leftover column info, making the result
+grid appear instead of the Messages tab (pgAdmin issue #8991)."""
+
+from unittest.mock import MagicMock, patch
+
+from pgadmin.utils.driver.psycopg3.connection import Connection
+from pgadmin.utils.driver.psycopg3.cursor import AsyncDictServerCursor
+from pgadmin.utils.route import BaseTestGenerator
+
+
+class ExecuteVoidServerCursorTest(BaseTestGenerator):
+
+    scenarios = [
+        ('COMMIT with a cached server-side cursor runs on a throwaway '
+         'plain cursor and clears stale column info', dict(sql='COMMIT;')),
+        ('ROLLBACK with a cached server-side cursor runs on a throwaway '
+         'plain cursor and clears stale column info',
+         dict(sql='ROLLBACK;')),
+    ]
+
+    def runTest(self):
+        manager = MagicMock(sid=1)
+        conn = Connection(manager, 'test-conn-id', 'testdb')
+        conn.python_encoding = 'utf-8'
+
+        # Leftover state from a previous SELECT executed through the
+        # server-side cursor.
+        conn.column_info = [{'name': 'x'}]
+        conn.row_count = 1
+
+        server_cursor = MagicMock(spec=AsyncDictServerCursor)
+        server_cursor.closed = False
+
+        plain_cursor = MagicMock()
+        plain_cursor.closed = False
+
+        conn.conn = MagicMock()
+        conn.conn.cursor.return_value = plain_cursor
+        conn.conn.info.user = 'postgres'
+        conn.conn.info.host = 'localhost'
+        conn.conn.info.dbname = 'testdb'
+
+        # current_user needs a real request context to resolve at all;
+        # patch it only once inside that context, to a stand-in with the
+        # attribute execute_void()'s log line reads.
+        with self.app.test_request_context():
+            with patch(
+                'pgadmin.utils.driver.psycopg3.connection.current_user',
+                MagicMock(email='test@example.com')
+            ), patch.object(Connection, '_Connection__cursor',
+                            return_value=(True, server_cursor)):
+                status, result = conn.execute_void(self.sql)
+
+        self.assertTrue(status)
+        self.assertIsNone(result)
+
+        # The statement ran on the throwaway plain cursor, not the
+        # cached server-side one.
+        plain_cursor.execute.assert_called_once()
+        server_cursor.execute.assert_not_called()
+
+        # Stale result-set state from the prior SELECT must not leak
+        # into whatever poll() call comes next.
+        self.assertIsNone(conn.column_info)
+        self.assertEqual(conn.row_count, 0)