diff --git a/docs/generated/sql/bnf/begin_stmt.bnf b/docs/generated/sql/bnf/begin_stmt.bnf
deleted file mode 100644
index b76ee9186f8f..000000000000
--- a/docs/generated/sql/bnf/begin_stmt.bnf
+++ /dev/null
@@ -1,2 +0,0 @@
-begin_stmt ::=
-	'START' 'TRANSACTION' begin_transaction
diff --git a/docs/generated/sql/bnf/legacy_begin_stmt.bnf b/docs/generated/sql/bnf/legacy_begin_stmt.bnf
index f0c5585ba047..da259cc1e014 100644
--- a/docs/generated/sql/bnf/legacy_begin_stmt.bnf
+++ b/docs/generated/sql/bnf/legacy_begin_stmt.bnf
@@ -1,29 +1,19 @@
 legacy_begin_stmt ::=
-	'BEGIN' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'READ' 'UNCOMMITTED' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'READ' 'COMMITTED' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'SNAPSHOT' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'REPEATABLE' 'READ' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'SERIALIZABLE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'PRIORITY' 'LOW' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'PRIORITY' 'NORMAL' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'PRIORITY' 'HIGH' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'READ' 'ONLY' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'READ' 'WRITE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN' 'TRANSACTION' 'NOT' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	'BEGIN' 'TRANSACTION' 'PRIORITY' 'LOW' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN' 'TRANSACTION' 'PRIORITY' 'NORMAL' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN' 'TRANSACTION' 'PRIORITY' 'HIGH' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN' 'TRANSACTION' 'READ' 'ONLY' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN' 'TRANSACTION' 'READ' 'WRITE' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN' 'TRANSACTION' 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN' 'TRANSACTION' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN' 'TRANSACTION' 'NOT' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
 	| 'BEGIN' 'TRANSACTION' 
-	| 'BEGIN'  'ISOLATION' 'LEVEL' 'READ' 'UNCOMMITTED' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'ISOLATION' 'LEVEL' 'READ' 'COMMITTED' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'ISOLATION' 'LEVEL' 'SNAPSHOT' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'ISOLATION' 'LEVEL' 'REPEATABLE' 'READ' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'ISOLATION' 'LEVEL' 'SERIALIZABLE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'PRIORITY' 'LOW' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'PRIORITY' 'NORMAL' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'PRIORITY' 'HIGH' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'READ' 'ONLY' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'READ' 'WRITE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'AS' 'OF' 'SYSTEM' 'TIME' a_expr ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'DEFERRABLE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'BEGIN'  'NOT' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN'  'PRIORITY' 'LOW' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN'  'PRIORITY' 'NORMAL' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN'  'PRIORITY' 'HIGH' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN'  'READ' 'ONLY' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN'  'READ' 'WRITE' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN'  'AS' 'OF' 'SYSTEM' 'TIME' a_expr ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN'  'DEFERRABLE' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'BEGIN'  'NOT' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
 	| 'BEGIN'  
diff --git a/docs/generated/sql/bnf/set_transaction.bnf b/docs/generated/sql/bnf/set_transaction.bnf
index d8a1db215d37..973dde2b78ba 100644
--- a/docs/generated/sql/bnf/set_transaction.bnf
+++ b/docs/generated/sql/bnf/set_transaction.bnf
@@ -1,14 +1,9 @@
 set_transaction_stmt ::=
-	'SET' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'READ' 'UNCOMMITTED' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'READ' 'COMMITTED' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'SNAPSHOT' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'REPEATABLE' 'READ' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'ISOLATION' 'LEVEL' 'SERIALIZABLE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'PRIORITY' 'LOW' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'PRIORITY' 'NORMAL' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'PRIORITY' 'HIGH' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'READ' 'ONLY' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'READ' 'WRITE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
-	| 'SET' 'TRANSACTION' 'NOT' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'ISOLATION' 'LEVEL' ( 'READ' 'UNCOMMITTED' | 'READ' 'COMMITTED' | 'SNAPSHOT' | 'REPEATABLE' 'READ' | 'SERIALIZABLE' ) ) | ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	'SET' 'TRANSACTION' 'PRIORITY' 'LOW' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'SET' 'TRANSACTION' 'PRIORITY' 'NORMAL' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'SET' 'TRANSACTION' 'PRIORITY' 'HIGH' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'SET' 'TRANSACTION' 'READ' 'ONLY' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'SET' 'TRANSACTION' 'READ' 'WRITE' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'SET' 'TRANSACTION' 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'SET' 'TRANSACTION' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
+	| 'SET' 'TRANSACTION' 'NOT' 'DEFERRABLE' ( ( ( ',' |  ) ( ( 'PRIORITY' ( 'LOW' | 'NORMAL' | 'HIGH' ) ) | ( 'READ' 'ONLY' | 'READ' 'WRITE' ) | ( 'AS' 'OF' 'SYSTEM' 'TIME' a_expr ) | ( 'DEFERRABLE' | 'NOT' 'DEFERRABLE' ) ) ) )*
diff --git a/docs/generated/sql/bnf/set_transaction_stmt.bnf b/docs/generated/sql/bnf/set_transaction_stmt.bnf
deleted file mode 100644
index 3ce95cb05c13..000000000000
--- a/docs/generated/sql/bnf/set_transaction_stmt.bnf
+++ /dev/null
@@ -1,3 +0,0 @@
-set_transaction_stmt ::=
-	'SET' 'TRANSACTION' transaction_mode_list
-	| 'SET' 'SESSION' 'TRANSACTION' transaction_mode_list
diff --git a/docs/generated/sql/bnf/stmt_block.bnf b/docs/generated/sql/bnf/stmt_block.bnf
index b36af937b7a2..4ee6e58af28c 100644
--- a/docs/generated/sql/bnf/stmt_block.bnf
+++ b/docs/generated/sql/bnf/stmt_block.bnf
@@ -2155,8 +2155,7 @@ typename ::=
 	| simple_typename 'ARRAY'
 
 transaction_mode ::=
-	transaction_iso_level
-	| transaction_user_priority
+	transaction_user_priority
 	| transaction_read_mode
 	| as_of_clause
 	| transaction_deferrable_mode
@@ -2960,9 +2959,6 @@ opt_array_bounds ::=
 	'[' ']'
 	| 
 
-transaction_iso_level ::=
-	'ISOLATION' 'LEVEL' iso_level
-
 transaction_user_priority ::=
 	'PRIORITY' user_priority
 
@@ -3487,13 +3483,6 @@ interval_type ::=
 	| 'INTERVAL' interval_qualifier
 	| 'INTERVAL' '(' iconst32 ')'
 
-iso_level ::=
-	'READ' 'UNCOMMITTED'
-	| 'READ' 'COMMITTED'
-	| 'SNAPSHOT'
-	| 'REPEATABLE' 'READ'
-	| 'SERIALIZABLE'
-
 user_priority ::=
 	'LOW'
 	| 'NORMAL'
diff --git a/pkg/cmd/docgen/diagrams.go b/pkg/cmd/docgen/diagrams.go
index 9f21fa121de8..82dc81d95165 100644
--- a/pkg/cmd/docgen/diagrams.go
+++ b/pkg/cmd/docgen/diagrams.go
@@ -637,8 +637,6 @@ var specs = []stmtSpec{
 			"as_of_clause",
 			"transaction_deferrable_mode",
 			"user_priority",
-			"transaction_iso_level",
-			"iso_level",
 		},
 	},
 	{
@@ -1429,8 +1427,6 @@ var specs = []stmtSpec{
 			"as_of_clause",
 			"opt_comma",
 			"transaction_deferrable_mode",
-			"transaction_iso_level",
-			"iso_level",
 		},
 		match: []*regexp.Regexp{regexp.MustCompile("'SET' 'TRANSACTION'")},
 	},
diff --git a/pkg/sql/parser/sql.y b/pkg/sql/parser/sql.y
index 508aa82678d8..0ff0009f229d 100644
--- a/pkg/sql/parser/sql.y
+++ b/pkg/sql/parser/sql.y
@@ -12641,6 +12641,7 @@ opt_comma:
 transaction_mode:
   transaction_iso_level
   {
+    /* SKIP DOC */
     $$.val = tree.TransactionModes{Isolation: $1.isoLevel()}
   }
 | transaction_user_priority