MWL#90: Address review feedback part #1

mysql-test/include/mix1.inc

@@ -1532,12 +1532,6 @@ INSERT INTO t1 VALUES (1,1,1), (1,1,1), (1,1,2), (1,1,1), (1,1,2);
 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
                  FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
---echo # MariaDB note:
---echo #  This will show 2 for table which has 5 rows. 
---echo #  This is because the access method employed is actually range access
---echo #  which scans 2 records (yes, EXPLAIN displays it incorrectly).
---echo #  our correct printing is an artifact of changing in select_describe()
---echo #  from printing table->starts.records() to tab->records.
 EXPLAIN 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
                  FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
@@ -1551,7 +1545,6 @@ INSERT INTO t1 VALUES (1,1,1), (1,1,1), (1,1,2), (1,1,1), (1,1,2);
 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
                  FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
---echo # See above "MariaDB note"
 EXPLAIN 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
                  FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
@@ -1566,7 +1559,6 @@ INSERT INTO t1 VALUES (1,1,1), (1,1,1), (1,1,2), (1,1,1), (1,1,2);
 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
                  FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
---echo # See above "MariaDB note"
 EXPLAIN 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
                  FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;

mysql-test/suite/innodb/r/innodb_mysql.result

@@ -1735,12 +1735,6 @@ SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
 1
 1
-# MariaDB note:
-#  This will show 2 for table which has 5 rows. 
-#  This is because the access method employed is actually range access
-#  which scans 2 records (yes, EXPLAIN displays it incorrectly).
-#  our correct printing is an artifact of changing in select_describe()
-#  from printing table->starts.records() to tab->records.
 EXPLAIN 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
@@ -1755,7 +1749,6 @@ SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
 1
 1
-# See above "MariaDB note"
 EXPLAIN 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
@@ -1771,7 +1764,6 @@ SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
 1
 1
-# See above "MariaDB note"
 EXPLAIN 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;

mysql-test/suite/innodb_plugin/r/innodb_mysql.result

@@ -1735,12 +1735,6 @@ SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
 1
 1
-# MariaDB note:
-#  This will show 2 for table which has 5 rows. 
-#  This is because the access method employed is actually range access
-#  which scans 2 records (yes, EXPLAIN displays it incorrectly).
-#  our correct printing is an artifact of changing in select_describe()
-#  from printing table->starts.records() to tab->records.
 EXPLAIN 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
@@ -1755,7 +1749,6 @@ SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
 1
 1
-# See above "MariaDB note"
 EXPLAIN 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
@@ -1771,7 +1764,6 @@ SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
 1
 1
-# See above "MariaDB note"
 EXPLAIN 
 SELECT 1 FROM (SELECT COUNT(DISTINCT c1) 
 FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;

sql/item_subselect.cc

@@ -1022,7 +1022,7 @@ Item_in_subselect::Item_in_subselect(Item * left_exp,
 				     st_select_lex *select_lex):
   Item_exists_subselect(), left_expr_cache(0), first_execution(TRUE),
   is_constant(FALSE), optimizer(0), pushed_cond_guards(NULL),
-  exec_method(NOT_TRANSFORMED), upper_item(0)
+  exec_method(NOT_TRANSFORMED), is_flattenable_semijoin(FALSE), upper_item(0)
 {
   DBUG_ENTER("Item_in_subselect::Item_in_subselect");
   left_expr= left_exp;
@@ -4080,7 +4080,7 @@ void subselect_hash_sj_engine::cleanup()
 
 int subselect_hash_sj_engine::optimize()
 {
-  int res= 0;
+  int res;
   SELECT_LEX *save_select= thd->lex->current_select;
   thd->lex->current_select= materialize_join->select_lex;
   res= materialize_join->optimize();

sql/item_subselect.h

@@ -406,11 +406,6 @@ class Item_in_subselect :public Item_exists_subselect
   */
   bool is_flattenable_semijoin;
   
-  /*
-    Cost to populate the temporary table (set on if-needed basis).
-  */
-  //double startup_cost;
-
   bool *get_cond_guard(int i)
   {
     return pushed_cond_guards ? pushed_cond_guards + i : NULL;

sql/sql_join_cache.h

@@ -650,8 +650,6 @@ class JOIN_CACHE :public Sql_alloc
     buff= 0;
   }   
   
-  // JOIN_TAB *get_next_table(JOIN_TAB *tab);
-  
   friend class JOIN_CACHE_HASHED;
   friend class JOIN_CACHE_BNL;
   friend class JOIN_CACHE_BKA;

sql/sql_select.cc

@@ -242,9 +242,6 @@ static uint make_join_orderinfo(JOIN *join);
 Item_equal *find_item_equal(COND_EQUAL *cond_equal, Field *field,
                             bool *inherited_fl);
 
-JOIN_TAB *first_linear_tab(JOIN *join, bool after_const_tables);
-JOIN_TAB *next_linear_tab(JOIN* join, JOIN_TAB* tab, bool include_bush_roots);
-
 /**
   This handles SELECT with and without UNION.
 */
@@ -8569,6 +8566,12 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
     tab->sorted= sorted;
     sorted= 0;                                  // only first must be sorted
     
+
+    /*
+      We should not set tab->next_select for the last table in the
+      SMJ-nest, as setup_sj_materialization() has already set it to
+      end_sj_materialize.
+    */
     if (!(tab->bush_root_tab && 
           tab->bush_root_tab->bush_children->end == tab + 1))
     {
@@ -12910,7 +12913,6 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 	 i < field_count;
 	 i++, reg_field++, key_part_info++)
     {
-      key_part_info->null_bit=0;
       key_part_info->field=    *reg_field;
       (*reg_field)->flags |= PART_KEY_FLAG;
       if (key_part_info == keyinfo->key_part)

sql/sql_select.h

@@ -616,7 +616,6 @@ inline bool sj_is_materialize_strategy(uint strategy)
   return strategy >= SJ_OPT_MATERIALIZE;
 }
 
-
 class JOIN_TAB_RANGE: public Sql_alloc
 {
 public:
@@ -1050,6 +1049,9 @@ class JOIN :public Sql_alloc
 };
 
 
+JOIN_TAB *first_linear_tab(JOIN *join, bool after_const_tables);
+JOIN_TAB *next_linear_tab(JOIN* join, JOIN_TAB* tab, bool include_bush_roots);
+
 typedef struct st_select_check {
   uint const_ref,reg_ref;
 } SELECT_CHECK;

sql/sql_show.cc

@@ -6584,9 +6584,6 @@ int make_schema_select(THD *thd, SELECT_LEX *sel,
 }
 
 
-JOIN_TAB *first_linear_tab(JOIN *join, bool after_const_tables);
-JOIN_TAB *next_linear_tab(JOIN* join, JOIN_TAB* tab, bool include_bush_roots);
-
 /*
   Fill temporary schema tables before SELECT
 

sql/table.cc

@@ -5335,6 +5335,13 @@ bool st_table::is_children_attached(void)
 }
 
 
+/*
+  Return TRUE if the table is filled at execution phase 
+  
+  (and so, the optimizer must not do anything that depends on the contents of
+   the table, like range analysis or constant table detection)
+*/
+
 bool st_table::is_filled_at_execution()
 { 
   return test(pos_in_table_list->jtbm_subselect);

sql/table.h

@@ -968,9 +968,9 @@ struct st_table {
     DBUG_VOID_RETURN;
   }
   /*
-    If TRUE, the table is filled at execution phase (and so, the optimizer 
-    should not do things like range analysis or constant table detection on
-    it).
+    Returns TRUE if the table is filled at execution phase (and so, the
+    optimizer must not do anything that depends on the contents of the table,
+    like range analysis or constant table detection)
   */
   bool is_filled_at_execution();
   inline void disable_keyread()