Bug#45989 memory leak after explain encounters an error in the query

Memory allocated in TMP_TABLE_PARAM::copy_field is not cleaned up.
The fix is to clean up TMP_TABLE_PARAM::copy_field array in JOIN::destroy.


mysql-test/r/explain.result:
  test result
mysql-test/t/explain.test:
  test case
sql/sql_select.cc:
  Memory allocated in TMP_TABLE_PARAM::copy_field is not cleaned up.
  The fix is to clean up TMP_TABLE_PARAM::copy_field array in JOIN::destroy.

mysql-test/r/explain.result

@@ -159,3 +159,11 @@ CREATE TABLE t1 (a INT PRIMARY KEY);
 EXPLAIN EXTENDED SELECT COUNT(a) FROM t1 USE KEY(a);
 ERROR HY000: Key 'a' doesn't exist in table 't1'
 DROP TABLE t1;
+CREATE TABLE t1(a LONGTEXT);
+INSERT INTO t1 VALUES (repeat('a',@@global.max_allowed_packet));
+INSERT INTO t1 VALUES (repeat('b',@@global.max_allowed_packet));
+EXPLAIN SELECT DISTINCT 1 FROM t1,
+(SELECT DISTINCTROW a AS away FROM t1 GROUP BY a WITH ROLLUP) as d1
+WHERE t1.a = d1.a;
+ERROR 42S22: Unknown column 'd1.a' in 'where clause'
+DROP TABLE t1;

mysql-test/t/explain.test

@@ -135,5 +135,16 @@ EXPLAIN EXTENDED SELECT COUNT(a) FROM t1 USE KEY(a);
 
 DROP TABLE t1;
 
+#
+# Bug#45989 memory leak after explain encounters an error in the query
+#
+CREATE TABLE t1(a LONGTEXT);
+INSERT INTO t1 VALUES (repeat('a',@@global.max_allowed_packet));
+INSERT INTO t1 VALUES (repeat('b',@@global.max_allowed_packet));
+--error ER_BAD_FIELD_ERROR
+EXPLAIN SELECT DISTINCT 1 FROM t1,
+        (SELECT DISTINCTROW a AS away FROM t1 GROUP BY a WITH ROLLUP) as d1
+         WHERE t1.a = d1.a;
+DROP TABLE t1;
 
 # End of 5.0 tests.

sql/sql_select.cc

@@ -2176,7 +2176,7 @@ JOIN::destroy()
       }
     }
     tmp_join->tmp_join= 0;
-    tmp_table_param.copy_field=0;
+    tmp_table_param.cleanup();
     DBUG_RETURN(tmp_join->destroy());
   }
   cond_equal= 0;