Cap Oracle fetch buffers to requested rows

sqlit/domains/connections/providers/oracle/adapter.py

@@ -384,9 +384,10 @@ def execute_query(self, conn: Any, query: str, max_rows: int | None = None) -> t
         cursor = conn.cursor()
         try:
             # Larger fetch batches cut per-round-trip overhead on high-latency
-            # links (oracledb defaults: arraysize=100, prefetchrows=2).
-            cursor.arraysize = 1000
-            cursor.prefetchrows = 1001
+            # links without fetching beyond the requested result cap.
+            row_budget = max_rows + 1 if max_rows is not None else 1001
+            cursor.arraysize = min(1000, max(1, row_budget))
+            cursor.prefetchrows = min(1001, max(1, row_budget))
             cursor.execute(_prepare_statement(query))
             if cursor.description:
                 columns = [col[0] for col in cursor.description]

tests/connections/providers/oracle/test_statement_execution.py

@@ -43,6 +43,30 @@ def test_execute_query_removes_sql_statement_terminator(
     mock_conn.cursor.return_value.execute.assert_called_once_with(expected)
 
 
+@pytest.mark.parametrize(
+    ("max_rows", "expected_arraysize", "expected_prefetchrows"),
+    [
+        (None, 1000, 1001),
+        (1, 2, 2),
+        (999, 1000, 1000),
+        (1000, 1000, 1001),
+    ],
+)
+def test_execute_query_caps_fetch_buffers_to_requested_rows(
+    adapter: OracleAdapter,
+    mock_conn: MagicMock,
+    max_rows: int | None,
+    expected_arraysize: int,
+    expected_prefetchrows: int,
+) -> None:
+    """Small result limits must not prefetch hundreds of discarded rows."""
+    adapter.execute_query(mock_conn, "SELECT 1 FROM DUAL", max_rows=max_rows)
+
+    cursor = mock_conn.cursor.return_value
+    assert cursor.arraysize == expected_arraysize
+    assert cursor.prefetchrows == expected_prefetchrows
+
+
 def test_execute_non_query_removes_sql_statement_terminator(
     adapter: OracleAdapter,
     mock_conn: MagicMock,