From 904ac415e4b135a14033fe792bb1045feec648fa Mon Sep 17 00:00:00 2001
From: Leonid Fedorov <leonid.fedorov@mariadb.com>
Date: Tue, 26 Mar 2024 14:17:40 +0000
Subject: [PATCH] fix(plugin) MCOL-5699: throw error for unimplemented
 INTERSECT and EXCEPT

---
 dbcon/mysql/ha_mcs_execplan.cpp               | 15 +++++++++
 .../columnstore/bugfixes/MCOL-5699.result     | 33 +++++++++++++++++++
 .../columnstore/bugfixes/MCOL-5699.test       | 25 ++++++++++++++
 3 files changed, 73 insertions(+)
 create mode 100644 mysql-test/columnstore/bugfixes/MCOL-5699.result
 create mode 100644 mysql-test/columnstore/bugfixes/MCOL-5699.test

diff --git a/dbcon/mysql/ha_mcs_execplan.cpp b/dbcon/mysql/ha_mcs_execplan.cpp
index e88fcbec9..efcb9586f 100644
--- a/dbcon/mysql/ha_mcs_execplan.cpp
+++ b/dbcon/mysql/ha_mcs_execplan.cpp
@@ -6742,6 +6742,21 @@ int processFrom(bool& isUnion, SELECT_LEX& select_lex, gp_walk_info& gwi, SCSEP&
   // Existed pushdown handlers won't get in this scope
   // MDEV-25080 Union pushdown would enter this scope
   // is_unit_op() give a segv for derived_handler's SELECT_LEX
+
+  // check INTERSECT or EXCEPT, that are not implemented
+  auto * nextSelect = select_lex.master_unit()->first_select()->next_select();
+  if (nextSelect)
+  {
+    if (nextSelect->get_linkage() == INTERSECT_TYPE)
+    {
+      setError(gwi.thd, ER_INTERNAL_ERROR, "INTERSECT is not supported by Columnstore engine", gwi);
+    }
+    else if (nextSelect->get_linkage() == EXCEPT_TYPE)
+    {
+      setError(gwi.thd, ER_INTERNAL_ERROR, "EXCEPT is not supported by Columnstore engine", gwi);
+    }
+  }
+
   if (!isUnion && (!isSelectHandlerTop || isSelectLexUnit) && select_lex.master_unit()->is_unit_op())
   {
     // MCOL-2178 isUnion member only assigned, never used
diff --git a/mysql-test/columnstore/bugfixes/MCOL-5699.result b/mysql-test/columnstore/bugfixes/MCOL-5699.result
new file mode 100644
index 000000000..d89cfe5c4
--- /dev/null
+++ b/mysql-test/columnstore/bugfixes/MCOL-5699.result
@@ -0,0 +1,33 @@
+DROP DATABASE IF EXISTS mcol_5699 ;
+CREATE DATABASE mcol_5699 ;
+USE mcol_5699 ;
+CREATE TABLE cs1(a text) ENGINE=columnstore;
+INSERT INTO cs1 VALUES('a'),('b'),('c'),('x');
+CREATE TABLE cs2(a text) ENGINE=columnstore;
+INSERT INTO cs1 VALUES('y'),('z'),('x');
+SELECT a from cs1 UNION ALL select a from cs2;
+a
+a
+b
+c
+x
+y
+z
+x
+SELECT a from cs1 UNION DISTINCT select a from cs2;
+a
+a
+b
+c
+x
+y
+z
+SELECT a from cs1 INTERSECT ALL select a from cs2;
+ERROR HY000: Internal error: INTERSECT is not supported by Columnstore engine
+SELECT a from cs1 INTERSECT DISTINCT select a from cs2;
+ERROR HY000: Internal error: INTERSECT is not supported by Columnstore engine
+SELECT a from cs1 EXCEPT ALL select a from cs2;
+ERROR HY000: Internal error: EXCEPT is not supported by Columnstore engine
+SELECT a from cs1 EXCEPT DISTINCT select a from cs2;
+ERROR HY000: Internal error: EXCEPT is not supported by Columnstore engine
+DROP DATABASE mcol_5699 ;
diff --git a/mysql-test/columnstore/bugfixes/MCOL-5699.test b/mysql-test/columnstore/bugfixes/MCOL-5699.test
new file mode 100644
index 000000000..6b7e25349
--- /dev/null
+++ b/mysql-test/columnstore/bugfixes/MCOL-5699.test
@@ -0,0 +1,25 @@
+--source ../include/have_columnstore.inc
+--disable_warnings
+DROP DATABASE IF EXISTS mcol_5699 ;
+--enable_warnings
+CREATE DATABASE mcol_5699 ;
+USE mcol_5699 ;
+CREATE TABLE cs1(a text) ENGINE=columnstore;
+INSERT INTO cs1 VALUES('a'),('b'),('c'),('x');
+
+CREATE TABLE cs2(a text) ENGINE=columnstore;
+INSERT INTO cs1 VALUES('y'),('z'),('x');
+
+SELECT a from cs1 UNION ALL select a from cs2;
+SELECT a from cs1 UNION DISTINCT select a from cs2;
+
+--ERROR 1815
+SELECT a from cs1 INTERSECT ALL select a from cs2;
+--ERROR 1815
+SELECT a from cs1 INTERSECT DISTINCT select a from cs2;
+--ERROR 1815
+SELECT a from cs1 EXCEPT ALL select a from cs2;
+--ERROR 1815
+SELECT a from cs1 EXCEPT DISTINCT select a from cs2;
+
+DROP DATABASE mcol_5699 ;