Fixed bug mdev-11674.

1. The rows of a recursive CTE at some point may overflow
the HEAP temporary table containing them. At this point
the table is converted to a MyISAM temporary table and the
new added rows are placed into this MyISAM table.
A bug in the of select_union_recursive::send_data prevented
the server from writing the row that caused the overflow
into the temporary table used for the result of the iteration
steps. This could lead, in particular,to a premature end
of the iterations.
2. The method TABLE::insert_all_rows_into() that was used
to copy all rows of one temporary table into another
did not take into account that the destination temporary
table must be converted to a MyISAM table at some point.
This patch fixed this problem. It also renamed the method
into TABLE::insert_all_rows_into_tmp_table() and added
an extra parameter needed for the conversion.

mysql-test/r/cte_recursive.result

@@ -2327,3 +2327,19 @@ a	b	dist
 7	6	3
 DROP VIEW edges2;
 DROP TABLE edges;
+#
+# MDEV-11674: recursive CTE table that cannot be stored
+#             in a heap table
+#
+create table t1 (id int, test_data varchar(36));
+insert into t1(id, test_data)
+select id, test_data
+from (
+with recursive data_generator(id, test_data) as (
+select 1 as id, uuid() as test_data
+union all
+select id + 1, uuid() from data_generator where id < 150000
+)
+select * from data_generator
+) as a;
+drop table t1;

mysql-test/t/cte_recursive.test

@@ -1484,3 +1484,24 @@ ORDER BY a, dist, b;
 
 DROP VIEW edges2;
 DROP TABLE edges;
+
+
+--echo #
+--echo # MDEV-11674: recursive CTE table that cannot be stored
+--echo #             in a heap table
+--echo #
+
+create table t1 (id int, test_data varchar(36));
+
+insert into t1(id, test_data)
+select id, test_data
+    from (
+        with recursive data_generator(id, test_data) as (
+                select 1 as id, uuid() as test_data
+                union all
+                select id + 1, uuid() from data_generator where id < 150000
+            )
+        select * from data_generator
+    ) as a;
+
+drop table t1;

sql/sql_derived.cc

@@ -969,7 +969,10 @@ bool TABLE_LIST::fill_recursive(THD *thd)
   if (!rc)
   {
     TABLE *src= with->rec_result->table;
-    rc =src->insert_all_rows_into(thd, table, true);
+    rc =src->insert_all_rows_into_tmp_table(thd,
+                                            table,
+                                            &with->rec_result->tmp_table_param,
+                                            true);
   } 
   return rc;
 }

sql/sql_union.cc

@@ -105,7 +105,7 @@ int select_union_recursive::send_data(List<Item> &values)
 {
   int rc= select_union::send_data(values);
 
-  if (!write_err)
+  if (write_err != HA_ERR_FOUND_DUPP_KEY)
   { 
     int err;
     if ((err= incr_table->file->ha_write_tmp_row(table->record[0])))
@@ -1192,6 +1192,7 @@ bool st_select_lex_unit::exec_recursive()
   st_select_lex *end= NULL;
   bool is_unrestricted= with_element->is_unrestricted();
   List_iterator_fast<TABLE> li(with_element->rec_result->rec_tables);
+  TMP_TABLE_PARAM *tmp_table_param= &with_element->rec_result->tmp_table_param;
   ha_rows examined_rows= 0;
   bool was_executed= executed;
   TABLE *rec_table;
@@ -1247,7 +1248,9 @@ bool st_select_lex_unit::exec_recursive()
   while ((rec_table= li++))
   {
     saved_error=
-      incr_table->insert_all_rows_into(thd, rec_table, !is_unrestricted);
+      incr_table->insert_all_rows_into_tmp_table(thd, rec_table,
+                                                 tmp_table_param,
+                                                 !is_unrestricted);
     if (!with_element->rec_result->first_rec_table_to_update)
       with_element->rec_result->first_rec_table_to_update= rec_table;
     if (with_element->level == 1)

sql/table.cc

@@ -7573,46 +7573,58 @@ bool TABLE::validate_default_values_of_unset_fields(THD *thd) const
 }
 
 
-bool TABLE::insert_all_rows_into(THD *thd, TABLE *dest, bool with_cleanup)
+bool TABLE::insert_all_rows_into_tmp_table(THD *thd,
+                                           TABLE *tmp_table,
+                                           TMP_TABLE_PARAM *tmp_table_param,
+                                           bool with_cleanup)
 {
   int write_err= 0;
 
-  DBUG_ENTER("TABLE::insert_all_rows_into");
+  DBUG_ENTER("TABLE::insert_all_rows_into_tmp_table");
 
   if (with_cleanup)
   {
-   if ((write_err= dest->file->ha_delete_all_rows()))
+   if ((write_err= tmp_table->file->ha_delete_all_rows()))
       goto err;
   }
    
   if (file->indexes_are_disabled())
-    dest->file->ha_disable_indexes(HA_KEY_SWITCH_ALL);
+    tmp_table->file->ha_disable_indexes(HA_KEY_SWITCH_ALL);
   file->ha_index_or_rnd_end();
 
   if (file->ha_rnd_init_with_error(1))
     DBUG_RETURN(1);
 
-  if (dest->no_rows)
+  if (tmp_table->no_rows)
-    dest->file->extra(HA_EXTRA_NO_ROWS);
+    tmp_table->file->extra(HA_EXTRA_NO_ROWS);
   else
   {
     /* update table->file->stats.records */
     file->info(HA_STATUS_VARIABLE);
-    dest->file->ha_start_bulk_insert(file->stats.records);
+    tmp_table->file->ha_start_bulk_insert(file->stats.records);
   }
 
-  while (!file->ha_rnd_next(dest->record[1]))
+  while (!file->ha_rnd_next(tmp_table->record[0]))
   {
-    write_err= dest->file->ha_write_tmp_row(dest->record[1]);
+    write_err= tmp_table->file->ha_write_tmp_row(tmp_table->record[0]);
     if (write_err)
-      goto err;
+    {
+      bool is_duplicate;
+      if (tmp_table->file->is_fatal_error(write_err, HA_CHECK_DUP) &&
+          create_internal_tmp_table_from_heap(thd, tmp_table,
+                                              tmp_table_param->start_recinfo, 
+                                              &tmp_table_param->recinfo,
+                                              write_err, 1, &is_duplicate))
+	DBUG_RETURN(1);
+       
+    }  
     if (thd->check_killed())
     {
       thd->send_kill_message();
       goto err_killed;
     }
   }
-  if (!dest->no_rows && dest->file->ha_end_bulk_insert())
+  if (!tmp_table->no_rows && tmp_table->file->ha_end_bulk_insert())
     goto err;
   DBUG_RETURN(0);
 

sql/table.h

@@ -53,6 +53,7 @@ class With_element;
 struct TDC_element;
 class Virtual_column_info;
 class Table_triggers_list;
+class TMP_TABLE_PARAM;
 
 /*
   Used to identify NESTED_JOIN structures within a join (applicable only to
@@ -1447,7 +1448,10 @@ public:
   inline Field **field_to_fill();
   bool validate_default_values_of_unset_fields(THD *thd) const;
 
-  bool insert_all_rows_into(THD *thd, TABLE *dest, bool with_cleanup);
+  bool insert_all_rows_into_tmp_table(THD *thd, 
+                                      TABLE *tmp_table,
+                                      TMP_TABLE_PARAM *tmp_table_param,
+                                      bool with_cleanup);
 };