[SHOW] EXPLAIN UPDATE/DELETE, code re-architecting

- Pass more tests
- select with subselects is now shown with type=PRIMARY where it used to be (incorrectly) 'SIMPLE' 

mysql-test/r/derived_view.result

@@ -386,7 +386,7 @@ materialized derived in merged derived
 explain extended  select * from (select * from 
 (select * from t1 where f1 < 7 group by f1) tt where f1 > 2) zz;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	<derived3>	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where
 3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where; Using temporary; Using filesort
 Warnings:
 Note	1003	select `tt`.`f1` AS `f1`,`tt`.`f11` AS `f11` from (select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f11` AS `f11` from `test`.`t1` where (`test`.`t1`.`f1` < 7) group by `test`.`t1`.`f1`) `tt` where (`tt`.`f1` > 2)
@@ -429,8 +429,8 @@ join
 (select * from (select * from t1 where f1 < 7 group by f1) tt where f1 > 2) z
 on x.f1 = z.f1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	<derived3>	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where
-1	SIMPLE	<derived5>	ref	key0	key0	5	tt.f1	2	100.00	
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where
+1	PRIMARY	<derived5>	ref	key0	key0	5	tt.f1	2	100.00	
 5	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where; Using temporary; Using filesort
 3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where; Using temporary; Using filesort
 Warnings:
@@ -522,7 +522,7 @@ materialized view in merged derived
 explain extended 
 select * from ( select * from v1 where f1 < 7) tt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	<derived3>	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where
 3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	11	100.00	Using temporary; Using filesort
 Warnings:
 Note	1003	select `v1`.`f1` AS `f1`,`v1`.`f11` AS `f11` from `test`.`v1` where (`v1`.`f1` < 7)
@@ -568,8 +568,8 @@ f1	f11
 join of above two
 explain extended select * from v6 join v7 on f2=f1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where
-1	SIMPLE	<derived5>	ref	key0	key0	5	test.t2.f2	2	100.00	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	11	100.00	Using where
+1	PRIMARY	<derived5>	ref	key0	key0	5	test.t2.f2	2	100.00	
 5	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	11	100.00	Using temporary; Using filesort
 Warnings:
 Note	1003	select `test`.`t2`.`f2` AS `f2`,`test`.`t2`.`f22` AS `f22`,`v1`.`f1` AS `f1`,`v1`.`f11` AS `f11` from `test`.`t2` join `test`.`v1` where ((`v1`.`f1` = `test`.`t2`.`f2`) and (`test`.`t2`.`f2` < 7) and (`test`.`t2`.`f2` in (2,3)))
@@ -1220,7 +1220,7 @@ Note	1003	select `test`.`t1`.`b` AS `b` from `test`.`t1` where 0
 EXPLAIN EXTENDED
 SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
 3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using temporary; Using filesort
 Warnings:
 Note	1003	select `v2`.`b` AS `b` from `test`.`v2` where 0

mysql-test/r/selectivity.result

@@ -393,7 +393,7 @@ and not exists (select * from orders where o_custkey = c_custkey)
 group by cntrycode
 order by cntrycode;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where; Using temporary; Using filesort
+1	PRIMARY	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where; Using temporary; Using filesort
 4	DEPENDENT SUBQUERY	orders	ref	i_o_custkey	i_o_custkey	5	dbt3_s001.customer.c_custkey	15	100.00	Using index
 3	SUBQUERY	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where
 Warnings:
@@ -434,7 +434,7 @@ and not exists (select * from orders where o_custkey = c_custkey)
 group by cntrycode
 order by cntrycode;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where; Using temporary; Using filesort
+1	PRIMARY	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where; Using temporary; Using filesort
 4	DEPENDENT SUBQUERY	orders	ref	i_o_custkey	i_o_custkey	5	dbt3_s001.customer.c_custkey	15	100.00	Using index
 3	SUBQUERY	customer	ALL	NULL	NULL	NULL	NULL	150	91.00	Using where
 Warnings:

mysql-test/r/selectivity_innodb.result

@@ -396,7 +396,7 @@ and not exists (select * from orders where o_custkey = c_custkey)
 group by cntrycode
 order by cntrycode;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where; Using temporary; Using filesort
+1	PRIMARY	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where; Using temporary; Using filesort
 4	DEPENDENT SUBQUERY	orders	ref	i_o_custkey	i_o_custkey	5	dbt3_s001.customer.c_custkey	15	100.00	Using index
 3	SUBQUERY	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where
 Warnings:
@@ -437,7 +437,7 @@ and not exists (select * from orders where o_custkey = c_custkey)
 group by cntrycode
 order by cntrycode;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where; Using temporary; Using filesort
+1	PRIMARY	customer	ALL	NULL	NULL	NULL	NULL	150	100.00	Using where; Using temporary; Using filesort
 4	DEPENDENT SUBQUERY	orders	ref	i_o_custkey	i_o_custkey	5	dbt3_s001.customer.c_custkey	15	100.00	Using index
 3	SUBQUERY	customer	ALL	NULL	NULL	NULL	NULL	150	91.00	Using where
 Warnings:

mysql-test/r/subselect2.result

@@ -258,7 +258,7 @@ WHERE date < '2012-12-12 12:12:12'
 ORDER BY mirror_date ASC
 ) AS calculated_result;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
 2	DERIVED	t1	range	date	date	9	NULL	2	Using index condition; Using where; Rowid-ordered scan; Using filesort
 SELECT * FROM (
 SELECT node_uid, date, mirror_date, @result := 0 AS result
@@ -281,7 +281,7 @@ WHERE date < '2012-12-12 12:12:12'
 ORDER BY mirror_date ASC
 ) AS calculated_result;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
 2	DERIVED	t1	range	date	date	9	NULL	2	Using index condition; Using where; Using filesort
 SELECT * FROM (
 SELECT node_uid, date, mirror_date, @result := 0 AS result

mysql-test/r/subselect_no_semijoin.result

@@ -13,7 +13,7 @@ select (select 2);
 2
 explain extended select (select 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1249	Select 2 was reduced during optimization
 Note	1003	select 2 AS `(select 2)`
@@ -737,7 +737,7 @@ id
 1
 EXPLAIN EXTENDED SELECT * FROM t2 WHERE id IN (SELECT 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	ref	id	id	5	const	1	100.00	Using index
+1	SIMPLE	t2	ref	id	id	5	const	1	100.00	Using index
 Warnings:
 Note	1249	Select 2 was reduced during optimization
 Note	1003	select `test`.`t2`.`id` AS `id` from `test`.`t2` where (`test`.`t2`.`id` = 1)
@@ -749,7 +749,7 @@ id
 2
 EXPLAIN EXTENDED SELECT * FROM t2 WHERE id IN (SELECT 1+(select 1));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	ref	id	id	5	const	1	100.00	Using where; Using index
+1	SIMPLE	t2	ref	id	id	5	const	1	100.00	Using where; Using index
 Warnings:
 Note	1249	Select 3 was reduced during optimization
 Note	1249	Select 2 was reduced during optimization
@@ -883,7 +883,7 @@ select 10.5 > ANY (SELECT * from t1);
 1
 explain extended select (select a+1) from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
 Warnings:
 Note	1276	Field or reference 'test.t1.a' of SELECT #2 was resolved in SELECT #1
 Note	1249	Select 2 was reduced during optimization
@@ -4552,7 +4552,7 @@ int_nokey	int_key
 0	0
 EXPLAIN EXTENDED SELECT * FROM C WHERE `int_key` IN (SELECT `int_nokey`);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	C	ALL	NULL	NULL	NULL	NULL	20	100.00	Using where
+1	SIMPLE	C	ALL	NULL	NULL	NULL	NULL	20	100.00	Using where
 DROP TABLE C;
 # End of test for bug#45061.
 #
@@ -6107,7 +6107,7 @@ FROM t1 AS sq4_alias1
 WHERE (sq4_alias1.col_varchar_key + NULL) IS NULL OR
 sq4_alias1.col_varchar_key = @var3 ) AS alias3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	<derived2>	system	NULL	NULL	NULL	NULL	0	const row not found
+1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	0	const row not found
 2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
 SELECT * FROM ( SELECT @var3:=12, sq4_alias1.*
 FROM t1 AS sq4_alias1
@@ -6152,7 +6152,7 @@ FROM t2 AS c_sq1_alias1
 WHERE (c_sq1_alias1.col_int_nokey != @var2
 OR c_sq1_alias1.pk != @var3)) ) AS alias3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 3	DEPENDENT SUBQUERY	c_sq1_alias1	system	PRIMARY	NULL	NULL	NULL	1	
 SELECT * FROM ( SELECT sq4_alias1.*
 FROM t1 AS sq4_alias1

sql/opt_qpf.cc

@@ -99,9 +99,9 @@ int QPF_union::print_explain(QPF_query *query, select_result_sink *output,
                              uint8 explain_flags)
 {
   // print all children, in order
-  for (int i= 0; i < (int) children.elements(); i++)
+  for (int i= 0; i < (int) union_members.elements(); i++)
   {
-    QPF_select *sel= query->get_select(children.at(i));
+    QPF_select *sel= query->get_select(union_members.at(i));
     sel->print_explain(query, output, explain_flags);
   }
 
@@ -123,15 +123,15 @@ int QPF_union::print_explain(QPF_query *query, select_result_sink *output,
     uint len= 6, lastop= 0;
     memcpy(table_name_buffer, STRING_WITH_LEN("<union"));
 
-    for (; childno < children.elements() && len + lastop + 5 < NAME_LEN;
+    for (; childno < union_members.elements() && len + lastop + 5 < NAME_LEN;
          childno++)
     {
       len+= lastop;
       lastop= my_snprintf(table_name_buffer + len, NAME_LEN - len,
-                          "%u,", children.at(childno));
+                          "%u,", union_members.at(childno));
     }
 
-    if (childno < children.elements() || len + lastop >= NAME_LEN)
+    if (childno < union_members.elements() || len + lastop >= NAME_LEN)
     {
       memcpy(table_name_buffer + len, STRING_WITH_LEN("...>") + 1);
       len+= 4;
@@ -184,6 +184,13 @@ int QPF_union::print_explain(QPF_query *query, select_result_sink *output,
 
   if (output->send_data(item_list))
     return 1;
+
+  for (int i= 0; i < (int) children.elements(); i++)
+  {
+    QPF_node *node= query->get_node(children.at(i));
+    node->print_explain(query, output, explain_flags);
+  }
+
   return 0;
 }
 
@@ -222,7 +229,6 @@ int QPF_select::print_explain(QPF_query *query, select_result_sink *output,
 
     if (output->send_data(item_list))
       return 1;
-    return 0;
   }
   else
   {
@@ -244,7 +250,6 @@ int QPF_select::print_explain(QPF_query *query, select_result_sink *output,
     }
   }
 
-  //psergey-TODO: print children here...
   for (int i= 0; i < (int) children.elements(); i++)
   {
     QPF_node *node= query->get_node(children.at(i));
@@ -262,11 +267,17 @@ int QPF_table_access::print_explain(select_result_sink *output, uint8 explain_fl
   Item *item_null= new Item_null();
   //const CHARSET_INFO *cs= system_charset_info;
   
+  if (sjm_nest_select_id)
+    select_id= sjm_nest_select_id;
+
   /* `id` column */
   item_list.push_back(new Item_int((int32) select_id));
 
   /* `select_type` column */
-  push_str(&item_list, select_type);
+  if (sjm_nest_select_id)
+    push_str(&item_list, "MATERIALIZED");
+  else
+    push_str(&item_list, select_type);
 
   /* `table` column */
   push_string(&item_list, &table_name);
@@ -440,6 +451,18 @@ void QPF_table_access::append_tag_name(String *str, enum Extra_tag tag)
       str->append(join_buffer_type);
       break;
     }
+    case ET_FIRST_MATCH:
+    {
+      if (firstmatch_table_name.length())
+      {
+        str->append("FirstMatch(");
+        str->append(firstmatch_table_name);
+        str->append(")");
+      }
+      else
+        str->append(extra_tag_text[tag]);
+      break;
+    }
     default:
      str->append(extra_tag_text[tag]);
   }

sql/opt_qpf.h

@@ -23,6 +23,14 @@ class QPF_node : public Sql_alloc
   virtual enum qpf_node_type get_type()= 0;
   virtual int print_explain(QPF_query *query, select_result_sink *output, 
                             uint8 explain_flags)=0;
+
+
+  Dynamic_array<int> children;
+  void add_child(int select_no)
+  {
+    children.append(select_no);
+  }
+
   virtual ~QPF_node(){}
 };
 
@@ -90,13 +98,6 @@ class QPF_select : public QPF_node
   bool using_temporary;
   bool using_filesort;
   
-  /* Child selects. TODO: join this with QPF_union's children? */
-  Dynamic_array<int> children;
-  void add_child(int select_no)
-  {
-    children.append(select_no);
-  }
-
   void print_tabular(select_result_sink *output, uint8 explain_flags//, 
                      //bool *printed_anything
                     );
@@ -113,15 +114,26 @@ class QPF_union : public QPF_node
 
   int get_select_id()
   {
-    DBUG_ASSERT(children.elements() > 0);
-    return children.at(0);
+    DBUG_ASSERT(union_members.elements() > 0);
+    return union_members.at(0);
   }
-  // This has QPF_select children
-  Dynamic_array<int> children;
+  /*
+    Members of the UNION.  Note: these are disjoint from UNION's "children".
+    Example:
+
+      (select * from t1) union 
+      (select * from t2) order by (select col1 from t3 ...)
+
+    here 
+      - select-from-t1 and select-from-t2 are "union members"
+      - select-from-t3 is the only "child".
+    
+  */
+  Dynamic_array<int> union_members;
 
   void add_select(int select_no)
   {
-    children.append(select_no);
+    union_members.append(select_no);
   }
   void push_table_name(List<Item> *item_list);
   int print_explain(QPF_query *query, select_result_sink *output, 
@@ -204,56 +216,66 @@ class QPF_table_access : public Sql_alloc
 
   /* Internals */
 public:
+  /* 
+    0 means this tab is not inside SJM nest and should use QPF_select's id
+    other value means the tab is inside an SJM nest.
+  */
+  int sjm_nest_select_id;
+
   /* id and 'select_type' are cared-of by the parent QPF_select */
   TABLE *table;
-  StringBuffer<256> table_name;
+  StringBuffer<64> table_name;
 
   enum join_type type;
 
-  StringBuffer<256> used_partitions;
+  StringBuffer<64> used_partitions;
   bool used_partitions_set;
 
   key_map possible_keys;
-  StringBuffer<256> possible_keys_str;
+  StringBuffer<64> possible_keys_str;
   
+  /* Not used? */
   uint key_no;
   uint key_length;
 
   Dynamic_array<enum Extra_tag> extra_tags;
 
   //temporary:
-  StringBuffer<256> key;
-  StringBuffer<256> key_len;
-  StringBuffer<256> ref;
-  bool key_set;
-  bool key_len_set;
-  bool ref_set;
+  bool key_set; /* not set means 'NULL' should be printed */
+  StringBuffer<64> key;
+
+  bool key_len_set; /* not set means 'NULL' should be printed */
+  StringBuffer<64> key_len;
+
+  bool ref_set; /* not set means 'NULL' should be printed */
+  StringBuffer<64> ref;
 
   bool rows_set;
   ha_rows rows;
 
-  double filtered;
   bool filtered_set;
+  double filtered;
 
   /* Various stuff for 'Extra' column*/
   uint join_cache_level;
   
   // Valid if ET_USING tag is present
-  StringBuffer<256> quick_info;
+  StringBuffer<64> quick_info;
 
   // Valid if ET_USING_INDEX_FOR_GROUP_BY is present
-  StringBuffer<256> loose_scan_type;
+  StringBuffer<64> loose_scan_type;
   
   // valid with ET_RANGE_CHECKED_FOR_EACH_RECORD
   key_map range_checked_map;
 
   // valid with ET_USING_MRR
-  StringBuffer <256> mrr_type;
+  StringBuffer <64> mrr_type;
 
   // valid with ET_USING_JOIN_BUFFER
-  StringBuffer <256> join_buffer_type;
+  StringBuffer <64> join_buffer_type;
   
-  TABLE *firstmatch_table;
+  //TABLE *firstmatch_table;
+  StringBuffer<64> firstmatch_table_name;
 
   int print_explain(select_result_sink *output, uint8 explain_flags, 
                     uint select_id, const char *select_type,

sql/sql_select.cc

@@ -22308,7 +22308,7 @@ void explain_append_mrr_info(QUICK_RANGE_SELECT *quick, String *res)
                                         sizeof(mrr_str_buf));
   if (len > 0)
   {
-    res->append(STRING_WITH_LEN("; "));
+    //res->append(STRING_WITH_LEN("; "));
     res->append(mrr_str_buf, len);
   }
 }
@@ -22929,7 +22929,7 @@ void append_possible_keys(String *str, TABLE *table, key_map possible_keys)
 int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
                    bool distinct, const char *message)
 {
-  QPF_select *qp_sel= NULL;
+  QPF_node *qp_node;
   const bool on_the_fly= true;
  
   JOIN *join= this; /* Legacy: this code used to be a non-member function */
@@ -22951,7 +22951,8 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
   */
   if (message)
   {
-    qp_sel= new QPF_select;
+    QPF_select *qp_sel;
+    qp_node= qp_sel= new QPF_select;
     join->select_lex->set_explain_type(on_the_fly);
 
     qp_sel->select_id= join->select_lex->select_number;
@@ -22964,6 +22965,7 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
   {
     select_lex->set_explain_type(on_the_fly);
     QPF_union *qp_union= new QPF_union;
+    qp_node= qp_union;
 
     SELECT_LEX *child;
     for (child= select_lex->master_unit()->first_select(); child;
@@ -22981,13 +22983,14 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
   else if (!join->select_lex->master_unit()->derived ||
            join->select_lex->master_unit()->derived->is_materialized_derived())
   {
-    qp_sel= new QPF_select;
+    QPF_select *qp_sel;
+    qp_node= qp_sel= new QPF_select;
     table_map used_tables=0;
 
     if (on_the_fly)
       join->select_lex->set_explain_type(on_the_fly);
 
-    bool printing_materialize_nest= FALSE;
+    //bool printing_materialize_nest= FALSE;
     uint select_id= join->select_lex->select_number;
 
     qp_sel->select_id= join->select_lex->select_number;
@@ -23002,7 +23005,7 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
       {
         JOIN_TAB *first_sibling= tab->bush_root_tab->bush_children->start;
         select_id= first_sibling->emb_sj_nest->sj_subq_pred->get_identifier();
-        printing_materialize_nest= TRUE;
+        //printing_materialize_nest= TRUE;
       }
       
       TABLE *table=tab->table;
@@ -23042,10 +23045,12 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
 
       QPF_table_access *qpt= new QPF_table_access;
       qp_sel->add_table(qpt);
-
+      
       /* id */
-      // TODO: this can be '2' in case of SJM nests..
-      //qp_sel->select_id= select_id;
+      if (tab->bush_root_tab)
+        qpt->sjm_nest_select_id= select_id;
+      else
+        qpt->sjm_nest_select_id= 0;
 
       /* select_type */
       //const char* stype= printing_materialize_nest? "MATERIALIZED" : 
@@ -23060,7 +23065,7 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
 	int len= my_snprintf(table_name_buffer, sizeof(table_name_buffer)-1,
 			     "<derived%u>",
 			     table->derived_select_number);
-	qpt->table_name.append(table_name_buffer, len, cs);
+	qpt->table_name.copy(table_name_buffer, len, cs);
       }
       else if (tab->bush_children)
       {
@@ -23070,12 +23075,12 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
                              sizeof(table_name_buffer)-1,
                              "<subquery%d>", 
                              ctab->emb_sj_nest->sj_subq_pred->get_identifier());
-	qpt->table_name.set(table_name_buffer, len, cs);
+	qpt->table_name.copy(table_name_buffer, len, cs);
       }
       else
       {
         TABLE_LIST *real_table= table->pos_in_table_list;
-	qpt->table_name.append(real_table->alias, strlen(real_table->alias), cs);
+	qpt->table_name.copy(real_table->alias, strlen(real_table->alias), cs);
       }
 
       /* "partitions" column */
@@ -23433,13 +23438,12 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
           else
           {
             qpt->push_extra(ET_FIRST_MATCH);
-            //TABLE *prev_table=tab->do_firstmatch->table;
+            TABLE *prev_table=tab->do_firstmatch->table;
             /*
               TODO: qpt->firstmatch_table...
               This must be a reference to another QPF element. Or, its index.
             */
-#if 0
-            extra.append(STRING_WITH_LEN("; FirstMatch("));
+            // extra.append(STRING_WITH_LEN("; FirstMatch("));
             if (prev_table->derived_select_number)
             {
               char namebuf[NAME_LEN];
@@ -23447,12 +23451,11 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
               int len= my_snprintf(namebuf, sizeof(namebuf)-1,
                                    "<derived%u>",
                                    prev_table->derived_select_number);
-              extra.append(namebuf, len);
+              qpt->firstmatch_table_name.append(namebuf, len);
             }
             else
-              extra.append(prev_table->pos_in_table_list->alias);
-            extra.append(STRING_WITH_LEN(")"));
-#endif
+              qpt->firstmatch_table_name.append(prev_table->pos_in_table_list->alias);
+            //extra.append(STRING_WITH_LEN(")"));
           }
         }
 
@@ -23484,20 +23487,17 @@ int JOIN::save_qpf(QPF_query *output, bool need_tmp_table, bool need_order,
 
   //TODO: can a UNION have subquery children that are not union members? yes,
   //perhaps...
-  if (qp_sel)
+  for (SELECT_LEX_UNIT *unit= join->select_lex->first_inner_unit();
+       unit;
+       unit= unit->next_unit())
   {
-    for (SELECT_LEX_UNIT *unit= join->select_lex->first_inner_unit();
-         unit;
-         unit= unit->next_unit())
+    /* 
+      Display subqueries only if they are not parts of eliminated WHERE/ON
+      clauses.
+    */
+    if (!(unit->item && unit->item->eliminated))
     {
-      /* 
-        Display subqueries only if they are not parts of eliminated WHERE/ON
-        clauses.
-      */
-      if (!(unit->item && unit->item->eliminated))
-      {
-        qp_sel->add_child(unit->first_select()->select_number);
-      }
+      qp_node->add_child(unit->first_select()->select_number);
     }
   }