Hi Sanja, Please find my feedback below. We should discuss it.
On Fri, Dec 19, 2014 at 01:24:12PM +0000, [email protected] wrote: > At file:///home/bell/maria/bzr/work-maria-5.5-MDEV-6892/ > > ------------------------------------------------------------ > revno: 4382 > revision-id: [email protected] > parent: [email protected] > committer: [email protected] > branch nick: work-maria-5.5-MDEV-6892 > timestamp: Fri 2014-12-19 14:23:50 +0100 > message: > MDEV-6892: WHERE does not apply > > Taking into account implicit dependence of constant view field from > nullable table of left join added. > > Fixed finding real table to check if ut turned to NULL (materialized view & > derived taken into account) ... > === modified file 'sql/item.cc' > --- a/sql/item.cc 2014-10-06 17:53:55 +0000 > +++ b/sql/item.cc 2014-12-19 13:23:50 +0000 > @@ -9790,12 +9790,36 @@ void Item_ref::update_used_tables() > (*ref)->update_used_tables(); > } > > +void Item_direct_view_ref::update_used_tables() > +{ > + if (view->is_inner_table_of_outer_join()) > + { > + null_ref_table= NULL; > + check_null_ref(); update_used_tables() is called during optimization. Why does it call check_null_ref() which may check null_ref_table->null_row? Is check_null_ref() function an execution-time function (and so it computes "current" value of an item) or is it an optimization-time function (and so it computes static attributes and can be called at any point in the query) It looks like it's a bit of both, which is really confusing. Could you please clarify? check_null_ref() was introduced by you in another views+outer joins bugfix. Can we get it documented? > + } > + Item_direct_ref::update_used_tables(); > +} Overall, I don't understand why some checks are in used_tables() and some are in update_used_tables(). Could you clarify? > + > table_map Item_direct_view_ref::used_tables() const > { > + TABLE *null_ref= null_ref_table; > + > + if (view->is_inner_table_of_outer_join()) > + { > + if (null_ref == NULL) > + null_ref= view->get_real_join_table(); > + else if (null_ref == NO_NULL_TABLE) > + null_ref= NULL; > + } > + else > + null_ref= NULL; > + > return get_depended_from() ? > OUTER_REF_TABLE_BIT : > ((view->is_merged_derived() || view->merged || !view->table) ? > - (*ref)->used_tables() : > + ((*ref)->used_tables() ? > + (*ref)->used_tables() : > + (null_ref ? null_ref->map : (table_map)0 )) : > view->table->map); Two-level nesting of conditional expressions is too complicated. Please change into 'if' statement and a comment about what's going on. How can Item_direct_view_ref() deped on an outer table?? > } > > > === modified file 'sql/item.h' > --- a/sql/item.h 2014-11-18 14:42:40 +0000 > +++ b/sql/item.h 2014-12-19 13:23:50 +0000 > @@ -3319,7 +3319,8 @@ class Item_direct_view_ref :public Item_ > { > if (null_ref_table == NULL) > { > - if (!(null_ref_table= view->get_real_join_table())) > + if (!view->is_inner_table_of_outer_join() || > + !(null_ref_table= view->get_real_join_table())) > null_ref_table= NO_NULL_TABLE; > } > if (null_ref_table != NO_NULL_TABLE && null_ref_table->null_row) > @@ -3329,6 +3330,7 @@ class Item_direct_view_ref :public Item_ > } > return FALSE; > } > + > public: > Item_direct_view_ref(Name_resolution_context *context_arg, Item **item, > const char *table_name_arg, > @@ -3353,8 +3355,10 @@ public: > bool subst_argument_checker(uchar **arg); > Item *equal_fields_propagator(uchar *arg); > Item *replace_equal_field(uchar *arg); > - table_map used_tables() const; > + table_map used_tables() const; > + void update_used_tables(); > table_map not_null_tables() const; > + bool const_item() const { return used_tables() == 0; } > bool walk(Item_processor processor, bool walk_subquery, uchar *arg) > { > return (*ref)->walk(processor, walk_subquery, arg) || > > === modified file 'sql/table.cc' > --- a/sql/table.cc 2014-10-29 10:22:48 +0000 > +++ b/sql/table.cc 2014-12-19 13:23:50 +0000 The function get_real_join_table() lacks comments, which makes it difficult to review. Do I understand correctly that its action can be described by this comment: /* @brief Given a merged view (or a merged derived table), find its first* base** table. @detail (*) first means as defined in the syntax (**) base means we need a physical table, one that has a bit in table->map and is present in select_lex->leaf_tables. Example: t1 join ( (select * from t2, t3 ) as derivedA join (select * from t5, t6) as derivedC ) as derivedB here, derivedB->get_real_join_table()="t2" */ > @@ -5012,7 +5012,8 @@ TABLE *TABLE_LIST::get_real_join_table() > TABLE_LIST *tbl= this; > while (tbl->table == NULL || tbl->table->reginfo.join_tab == NULL) I'm quite surprised that joins are run over tables that don't have reginfo.join_tab set appropriately... > { > - if (tbl->view == NULL && tbl->derived == NULL) > + if ((tbl->view == NULL && tbl->derived == NULL) || > + tbl->is_materialized_derived()) I'm wondering why part of conditions are in while(...) and the other part is here. > break; > /* we do not support merging of union yet */ > DBUG_ASSERT(tbl->view == NULL || > The code below this line looks bizarre (and it is still from your recent fixes to VIEWs): { List_iterator_fast<TABLE_LIST> ti; { List_iterator_fast<TABLE_LIST> ti(tbl->view != NULL ? why define 'ti' and then immediately redefine it? BR Sergei -- Sergei Petrunia, Software Developer MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
