fix(core): MTR + Double prepare on lex unit for ctas with union(#226)

mysql-test/suite/tianmu/r/issue226.result

@@ -0,0 +1,13 @@
+use test;
+CREATE TABLE t1 (f1 VARCHAR(255) CHARACTER SET utf8) ENGINE=TIANMU;
+CREATE TABLE t2 AS SELECT LEFT(f1,171) AS f2 FROM t1 UNION SELECT LEFT(f1,171) AS f2 FROM t1;
+INSERT INTO t2 VALUES ('a');
+INSERT INTO t2 VALUES ('b');
+INSERT INTO t2 VALUES ('c');
+SELECT * FROM t2;
+f2
+a
+b
+c
+DROP TABLE t1;
+DROP TABLE t2;

mysql-test/suite/tianmu/t/issue226.test

@@ -0,0 +1,9 @@
+use test;
+CREATE TABLE t1 (f1 VARCHAR(255) CHARACTER SET utf8) ENGINE=TIANMU;
+CREATE TABLE t2 AS SELECT LEFT(f1,171) AS f2 FROM t1 UNION SELECT LEFT(f1,171) AS f2 FROM t1;
+INSERT INTO t2 VALUES ('a');
+INSERT INTO t2 VALUES ('b');
+INSERT INTO t2 VALUES ('c');
+SELECT * FROM t2;
+DROP TABLE t1;
+DROP TABLE t2;

storage/tianmu/core/engine_execute.cpp

@@ -598,7 +598,7 @@ int st_select_lex_unit::optimize_for_tianmu() {
 
             if (!join->is_optimized()) {
                 //    saved_error = join->prepare(fake_select_lex->table_list.first, 0, 0,
-                //    global_parameters->order_list.elements,
+                //                                global_parameters->order_list.elements,
                 //                                global_parameters->order_list.first, NULL, NULL, fake_select_lex,
                 //                                this); //STONEDB UPGRADE
                 if(!is_prepared()) {