Fix buildbot failures:

- JOIN::prepare would have set JOIN::table_count to incorrect value (bad merge of MWL 106)
- optimize_keyuse() would use table-bit as table number
  (the change in optimize_keyuse is also the reason for query plan changes. Not 
   expected to have much effect because only handles cases of no index statistics)
- st_select_lex::register_dependency_item() ignored the fact that some of the 
  selects on the dependency paths could have been merged to their parents (because they 
  were mergeable VIEWs)
- Undo the incorrect fix in Item_subselect::recalc_used_tables(): do not call 
  fix_after_pullout() for Item_subselect::Ref_to_outside members. 

mysql-test/r/subselect.result

@@ -1342,7 +1342,7 @@ a
 explain extended select * from t2 where t2.a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using where; Using index
-1	PRIMARY	t1	ref	a	a	5	test.t2.a	100	100.00	Using index; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	101	100.00	Using index; FirstMatch(t2)
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where (`test`.`t1`.`a` = `test`.`t2`.`a`)
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
@@ -1352,7 +1352,7 @@ a
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using where; Using index
-1	PRIMARY	t1	ref	a	a	5	test.t2.a	100	100.00	Using where; Using index; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	101	100.00	Using where; Using index; FirstMatch(t2)
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
 select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
@@ -1363,7 +1363,7 @@ explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using where; Using index
 1	PRIMARY	t3	index	a	a	5	NULL	3	100.00	Using where; Using index
-1	PRIMARY	t1	ref	a	a	10	test.t2.a,test.t3.a	11	100.00	Using index; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	10	test.t2.a,test.t3.a	116	100.00	Using index; FirstMatch(t2)
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` = `test`.`t3`.`a`))
 insert into t1 values (3,31);
@@ -1379,7 +1379,7 @@ a
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using where; Using index
-1	PRIMARY	t1	ref	a	a	5	test.t2.a	100	100.00	Using where; Using index; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	101	100.00	Using where; Using index; FirstMatch(t2)
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
 drop table t0, t1, t2, t3;

mysql-test/r/subselect_no_mat.result

@@ -1346,7 +1346,7 @@ a
 explain extended select * from t2 where t2.a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using where; Using index
-1	PRIMARY	t1	ref	a	a	5	test.t2.a	100	100.00	Using index; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	101	100.00	Using index; FirstMatch(t2)
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where (`test`.`t1`.`a` = `test`.`t2`.`a`)
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
@@ -1356,7 +1356,7 @@ a
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using where; Using index
-1	PRIMARY	t1	ref	a	a	5	test.t2.a	100	100.00	Using where; Using index; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	101	100.00	Using where; Using index; FirstMatch(t2)
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
 select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
@@ -1367,7 +1367,7 @@ explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using where; Using index
 1	PRIMARY	t3	index	a	a	5	NULL	3	100.00	Using where; Using index
-1	PRIMARY	t1	ref	a	a	10	test.t2.a,test.t3.a	11	100.00	Using index; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	10	test.t2.a,test.t3.a	116	100.00	Using index; FirstMatch(t2)
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` = `test`.`t3`.`a`))
 insert into t1 values (3,31);
@@ -1383,7 +1383,7 @@ a
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using where; Using index
-1	PRIMARY	t1	ref	a	a	5	test.t2.a	100	100.00	Using where; Using index; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	101	100.00	Using where; Using index; FirstMatch(t2)
 Warnings:
 Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
 drop table t0, t1, t2, t3;

mysql-test/r/subselect_sj.result

 drop table if exists t0, t1, t2, t3, t4, t10, t11, t12;
+drop view if exists v1, v2;
+drop procedure if exists p1;
 set @save_optimizer_switch=@@optimizer_switch;
 create table t0 (a int);
 insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

mysql-test/r/subselect_sj_jcl6.result

@@ -7,6 +7,8 @@ show variables like 'join_cache_level';
 Variable_name	Value
 join_cache_level	6
 drop table if exists t0, t1, t2, t3, t4, t10, t11, t12;
+drop view if exists v1, v2;
+drop procedure if exists p1;
 set @save_optimizer_switch=@@optimizer_switch;
 create table t0 (a int);
 insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

mysql-test/r/subselect_sj_mat.result

@@ -365,7 +365,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3a	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.a1' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` semi join (`test`.`t2`) semi join (`test`.`t2i` join `test`.`t3` `t3c`) where ((`test`.`t2`.`b2` = `test`.`t1`.`a2`) and (`test`.`t2i`.`b2` = `test`.`t3c`.`c2`) and (`test`.`t2`.`b1` = `test`.`t1`.`a1`) and (`test`.`t2i`.`b1` = `test`.`t3c`.`c1`) and (<expr_cache><`test`.`t2`.`b2`,`test`.`t1`.`a1`>(<in_optimizer>(`test`.`t2`.`b2`,<exists>(select `test`.`t3a`.`c2` from `test`.`t3` `t3a` where ((`test`.`t1`.`a1` = `test`.`t3a`.`c1`) and (<cache>(`test`.`t2`.`b2`) = `test`.`t3a`.`c2`))))) or <expr_cache><`test`.`t2`.`b2`>(<in_optimizer>(`test`.`t2`.`b2`,`test`.`t2`.`b2` in ( <materialize> (select `test`.`t3b`.`c2` from `test`.`t3` `t3b` where (`test`.`t3b`.`c2` like '%03') ), <primary_index_lookup>(`test`.`t2`.`b2` in <temporary table> on distinct_key where ((`test`.`t2`.`b2` = `<subquery4>`.`c2`))))))) and (`test`.`t3c`.`c2` > '0'))
+Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` semi join (`test`.`t2`) semi join (`test`.`t2i` join `test`.`t3` `t3c`) where ((`test`.`t2`.`b2` = `test`.`t1`.`a2`) and (`test`.`t2i`.`b2` = `test`.`t3c`.`c2`) and (`test`.`t2`.`b1` = `test`.`t1`.`a1`) and (`test`.`t2i`.`b1` = `test`.`t3c`.`c1`) and (<expr_cache><`test`.`t2`.`b2`,`test`.`t1`.`a1`>(<in_optimizer>(`test`.`t2`.`b2`,<exists>(select `test`.`t3a`.`c2` from `test`.`t3` `t3a` where ((`test`.`t3a`.`c1` = `test`.`t1`.`a1`) and (<cache>(`test`.`t2`.`b2`) = `test`.`t3a`.`c2`))))) or <expr_cache><`test`.`t2`.`b2`>(<in_optimizer>(`test`.`t2`.`b2`,`test`.`t2`.`b2` in ( <materialize> (select `test`.`t3b`.`c2` from `test`.`t3` `t3b` where (`test`.`t3b`.`c2` like '%03') ), <primary_index_lookup>(`test`.`t2`.`b2` in <temporary table> on distinct_key where ((`test`.`t2`.`b2` = `<subquery4>`.`c2`))))))) and (`test`.`t3c`.`c2` > '0'))
 select * from t1
 where (a1, a2) in (select b1, b2 from t2
 where b2 in (select c2 from t3 t3a where c1 = a1) or
@@ -504,7 +504,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 Warnings:
 Note	1276	Field or reference 'test.t1.a1' of SELECT #3 was resolved in SELECT #1
 Note	1276	Field or reference 'test.t1.a2' of SELECT #6 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` semi join (`test`.`t2`) semi join (`test`.`t2i` join `test`.`t3` `t3c`) where ((`test`.`t2i`.`b2` = `test`.`t1`.`a2`) and (`test`.`t2`.`b2` = `test`.`t1`.`a2`) and (`test`.`t3c`.`c2` = `test`.`t1`.`a2`) and (`test`.`t2i`.`b1` = `test`.`t1`.`a1`) and (`test`.`t2`.`b1` = `test`.`t1`.`a1`) and (`test`.`t3c`.`c1` = `test`.`t1`.`a1`) and (<expr_cache><`test`.`t2`.`b2`,`test`.`t1`.`a1`>(<in_optimizer>(`test`.`t2`.`b2`,<exists>(select `test`.`t3a`.`c2` from `test`.`t3` `t3a` where ((`test`.`t1`.`a1` = `test`.`t3a`.`c1`) and (<cache>(`test`.`t2`.`b2`) = `test`.`t3a`.`c2`))))) or <expr_cache><`test`.`t2`.`b2`>(<in_optimizer>(`test`.`t2`.`b2`,`test`.`t2`.`b2` in ( <materialize> (select `test`.`t3b`.`c2` from `test`.`t3` `t3b` where (`test`.`t3b`.`c2` like '%03') ), <primary_index_lookup>(`test`.`t2`.`b2` in <temporary table> on distinct_key where ((`test`.`t2`.`b2` = `<subquery4>`.`c2`))))))))
+Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` semi join (`test`.`t2`) semi join (`test`.`t2i` join `test`.`t3` `t3c`) where ((`test`.`t2i`.`b2` = `test`.`t1`.`a2`) and (`test`.`t2`.`b2` = `test`.`t1`.`a2`) and (`test`.`t3c`.`c2` = `test`.`t1`.`a2`) and (`test`.`t2i`.`b1` = `test`.`t1`.`a1`) and (`test`.`t2`.`b1` = `test`.`t1`.`a1`) and (`test`.`t3c`.`c1` = `test`.`t1`.`a1`) and (<expr_cache><`test`.`t2`.`b2`,`test`.`t1`.`a1`>(<in_optimizer>(`test`.`t2`.`b2`,<exists>(select `test`.`t3a`.`c2` from `test`.`t3` `t3a` where ((`test`.`t3a`.`c1` = `test`.`t1`.`a1`) and (<cache>(`test`.`t2`.`b2`) = `test`.`t3a`.`c2`))))) or <expr_cache><`test`.`t2`.`b2`>(<in_optimizer>(`test`.`t2`.`b2`,`test`.`t2`.`b2` in ( <materialize> (select `test`.`t3b`.`c2` from `test`.`t3` `t3b` where (`test`.`t3b`.`c2` like '%03') ), <primary_index_lookup>(`test`.`t2`.`b2` in <temporary table> on distinct_key where ((`test`.`t2`.`b2` = `<subquery4>`.`c2`))))))))
 explain extended
 select * from t1 where (a1, a2) in (select '1 - 01', '2 - 01');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

mysql-test/r/subselect_sj_nonmerged.result

@@ -75,7 +75,7 @@ t4.b in (select max(t2.a) from t1, t2 group by t2.b);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	5	Using where
 1	PRIMARY	<subquery3>	ALL	distinct_key	NULL	NULL	NULL	5	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	t4	ref	a	a	10	<subquery2>.max(t2.a),<subquery3>.max(t2.a)	11	
+1	PRIMARY	t4	ref	a	a	10	<subquery2>.max(t2.a),<subquery3>.max(t2.a)	12	
 3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using temporary
 3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using temporary

mysql-test/r/view.result

@@ -1256,8 +1256,8 @@ s1
 insert into t1 values (0);
 execute stmt1;
 s1
-1
 0
+1
 deallocate prepare stmt1;
 drop view v2;
 drop table t1, t2;

mysql-test/t/subselect_sj.test

@@ -3,6 +3,8 @@
 #
 --disable_warnings
 drop table if exists t0, t1, t2, t3, t4, t10, t11, t12;
+drop view if exists v1, v2;
+drop procedure if exists p1;
 --enable_warnings
 
 set @save_optimizer_switch=@@optimizer_switch;

sql/item_subselect.cc

@@ -476,10 +476,11 @@ void Item_subselect::recalc_used_tables(st_select_lex *new_parent,
           upper->item->walk(&Item::enumerate_field_refs_processor, FALSE,
                             (uchar*)&fixer);
           used_tables_cache |= fixer.used_tables;
-
+/*
           if (after_pullout)
             upper->item->fix_after_pullout(new_parent, &(upper->item));
           upper->item->update_used_tables();
+*/          
         }
       }
     }

sql/opt_subselect.cc

@@ -1224,6 +1224,7 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
     table_no++;
   }
   parent_join->table_count += subq_lex->join->table_count;
+  //parent_join->table_count += subq_lex->leaf_tables.elements;
 
   /* 
     Put the subquery's WHERE into semi-join's sj_on_expr

sql/sql_lex.cc

@@ -1897,6 +1897,10 @@ void st_select_lex::register_dependency_item(st_select_lex *def_sel,
   DBUG_ENTER("st_select_lex::register_dependency_item");
   DBUG_ASSERT(this != def_sel);
   DBUG_ASSERT(*dependency);
+  //psergey-add-stupid:
+  while (def_sel->merged_into)
+    def_sel= def_sel->merged_into;
+  //:eof
   do
   {
     /* check duplicates */

sql/sql_select.cc

@@ -558,7 +558,7 @@ JOIN::prepare(Item ***rref_pointer_array,
   List_iterator_fast<TABLE_LIST> li(select_lex->leaf_tables);
   while ((tbl= li++))
   {
-    table_count++; /* Count the number of tables in the join. */
+    //table_count++; /* Count the number of tables in the join. */
     /*
       If the query uses implicit grouping where the select list contains both
       aggregate functions and non-aggregate fields, any non-aggregated field
@@ -4761,12 +4761,15 @@ static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array)
 	(map= (keyuse->used_tables & ~join->const_table_map &
 	       ~OUTER_REF_TABLE_BIT)))
     {
-      uint tablenr;
-      tablenr= my_count_bits(map);
-      if (map == 1)			// Only one table
+      uint n_tables= my_count_bits(map);
+      if (n_tables == 1)			// Only one table
       {
+        Table_map_iterator it(map);
+        int tablenr= it.next_bit();
+        DBUG_ASSERT(tablenr != Table_map_iterator::BITMAP_END);
 	TABLE *tmp_table=join->table[tablenr];
-	keyuse->ref_table_rows= max(tmp_table->file->stats.records, 100);
+        if (tmp_table) // already created
+          keyuse->ref_table_rows= max(tmp_table->file->stats.records, 100);
       }
     }
     /*