[MCOL-4778] Return if we have an error in push_down_init. (#2420)

dbcon/mysql/ha_mcs_pushdown.cpp

@@ -962,6 +962,9 @@ select_handler* create_columnstore_select_handler(THD* thd, SELECT_LEX* select_l
       {
         my_printf_error(ER_INTERNAL_ERROR, "%s", MYF(0), "Error occured in ha_mcs_impl_pushdown_init()");
       }
+
+      // We had an error in `ha_mcs_impl_pushdown_init`, no need to continue execution of this query.
+      return handler;
     }
 
     // Unset select_lex::first_cond_optimization

mysql-test/columnstore/bugfixes/mcol-4778.result

@@ -0,0 +1,18 @@
+DROP DATABASE IF EXISTS mcol_4778;
+CREATE DATABASE mcol_4778;
+USE mcol_4778;
+CREATE TABLE bus_routes (origin varchar(50), dst varchar(50)) engine=columnstore;
+INSERT INTO bus_routes VALUES
+('New York', 'Boston'),
+('Boston', 'New York'),
+('New York', 'Washington'),
+('Washington', 'Boston'),
+('Washington', 'Raleigh');
+WITH RECURSIVE bus_dst as (
+SELECT origin as dst FROM bus_routes WHERE origin='New York'
+  UNION
+SELECT bus_routes.dst FROM bus_routes JOIN bus_dst ON bus_dst.dst = bus_routes.origin
+)
+SELECT * FROM bus_dst;
+ERROR 42000: The storage engine for the table doesn't support Recursive CTE
+DROP DATABASE mcol_4778;

mysql-test/columnstore/bugfixes/mcol-4778.test

@@ -0,0 +1,29 @@
+#
+# MCOL-4778 Recursive CTE Crashing MariaDB - fix crash produce err.
+#
+-- source ../include/have_columnstore.inc
+
+--disable_warnings
+DROP DATABASE IF EXISTS mcol_4778;
+--enable_warnings
+CREATE DATABASE mcol_4778;
+USE mcol_4778;
+
+CREATE TABLE bus_routes (origin varchar(50), dst varchar(50)) engine=columnstore;
+
+INSERT INTO bus_routes VALUES
+  ('New York', 'Boston'),
+  ('Boston', 'New York'),
+  ('New York', 'Washington'),
+  ('Washington', 'Boston'),
+  ('Washington', 'Raleigh');
+
+--error ER_CHECK_NOT_IMPLEMENTED
+WITH RECURSIVE bus_dst as (
+    SELECT origin as dst FROM bus_routes WHERE origin='New York'
+  UNION
+    SELECT bus_routes.dst FROM bus_routes JOIN bus_dst ON bus_dst.dst = bus_routes.origin
+)
+SELECT * FROM bus_dst;
+
+DROP DATABASE mcol_4778;