From e8f83121d20e2f5035e2e655c17014fbd56d1582 Mon Sep 17 00:00:00 2001
From: Denis Khalikov <dennis.khalikov@gmail.com>
Date: Sat, 18 Jun 2022 16:39:44 +0300
Subject: [PATCH] [MCOL-4778] Return if we have an error in push_down_init.

---
 dbcon/mysql/ha_mcs_pushdown.cpp               |  3 ++
 .../columnstore/bugfixes/mcol-4778.result     | 18 ++++++++++++
 .../columnstore/bugfixes/mcol-4778.test       | 29 +++++++++++++++++++
 3 files changed, 50 insertions(+)
 create mode 100644 mysql-test/columnstore/bugfixes/mcol-4778.result
 create mode 100644 mysql-test/columnstore/bugfixes/mcol-4778.test

diff --git a/dbcon/mysql/ha_mcs_pushdown.cpp b/dbcon/mysql/ha_mcs_pushdown.cpp
index 619caff4c..2d6c2120c 100644
--- a/dbcon/mysql/ha_mcs_pushdown.cpp
+++ b/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
diff --git a/mysql-test/columnstore/bugfixes/mcol-4778.result b/mysql-test/columnstore/bugfixes/mcol-4778.result
new file mode 100644
index 000000000..80c6fdd29
--- /dev/null
+++ b/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;
diff --git a/mysql-test/columnstore/bugfixes/mcol-4778.test b/mysql-test/columnstore/bugfixes/mcol-4778.test
new file mode 100644
index 000000000..ed8566740
--- /dev/null
+++ b/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;