Fix BEGIN READ WRITE regression for Redshift syntax

Redshift allows BEGIN with transaction mode modifiers such as READ WRITE or ISOLATION LEVEL. Treat those tokens like transaction starters so split() does not mistake BEGIN for a procedural block.

Author: divaltor

sqlparse/engine/statement_splitter.py

@@ -67,7 +67,8 @@ def _change_splitlevel(self, ttype, value):
                 (ttype is T.Keyword or ttype is T.Name) and \
                 unified in ('TRANSACTION', 'WORK', 'TRAN',
                             'DISTRIBUTED', 'DEFERRED',
-                            'IMMEDIATE', 'EXCLUSIVE'):
+                            'IMMEDIATE', 'EXCLUSIVE',
+                            'ISOLATION', 'READ'):
             self._begin_depth = max(0, self._begin_depth - 1)
             self._seen_begin = False
             return 0

tests/test_split.py

@@ -284,3 +284,31 @@ def test_split_begin_transaction_formatted():  # issue826
     assert stmts[1].startswith('DELETE')
     assert stmts[2].startswith('INSERT')
     assert stmts[3] == 'END\nTRANSACTION;'
+
+
+# https://github.com/andialbrecht/sqlparse/issues/843
+def test_split_begin_read_write():
+    # Redshift BEGIN READ WRITE should not be treated as a block start
+    sql = """BEGIN READ WRITE;
+DELETE FROM schema.table_a USING table_a_temp
+WHERE schema.table_a.id = table_a_temp.id;
+INSERT INTO schema.table_a SELECT * FROM table_a_temp;
+END TRANSACTION;"""
+    stmts = sqlparse.split(sql)
+    assert len(stmts) == 4
+    assert stmts[0] == 'BEGIN READ WRITE;'
+    assert stmts[1].startswith('DELETE')
+    assert stmts[2].startswith('INSERT')
+    assert stmts[3] == 'END TRANSACTION;'
+
+
+# https://github.com/andialbrecht/sqlparse/issues/843
+def test_split_begin_isolation_level_read_only():
+    sql = """BEGIN ISOLATION LEVEL SERIALIZABLE READ ONLY;
+SELECT 1;
+END TRANSACTION;"""
+    stmts = sqlparse.split(sql)
+    assert len(stmts) == 3
+    assert stmts[0] == 'BEGIN ISOLATION LEVEL SERIALIZABLE READ ONLY;'
+    assert stmts[1] == 'SELECT 1;'
+    assert stmts[2] == 'END TRANSACTION;'