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Mistakes corrected.

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TVC can be used in IN subquery and in PARTITION BY struct now.
Special variable to control working of optimization added.
This commit is contained in:
Galina Shalygina
2017-10-28 20:54:18 +02:00
parent 75370a58f4
commit a4ded0a9b5
34 changed files with 826 additions and 80 deletions
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97
sql/sql_tvc.cc
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@ -195,6 +195,7 @@ bool table_value_constr::prepare(THD *thd, SELECT_LEX *sl,
st_select_lex_unit *unit_arg)
{
DBUG_ENTER("table_value_constr::prepare");
select_lex->in_tvc= true;
List_iterator_fast<List_item> li(lists_of_values);
List_item *first_elem= li++;
@ -237,6 +238,7 @@ bool table_value_constr::prepare(THD *thd, SELECT_LEX *sl,
if (result && result->prepare(sl->item_list, unit_arg))
DBUG_RETURN(true);
select_lex->in_tvc= false;
DBUG_RETURN(false);
}
@ -496,6 +498,94 @@ static bool create_tvc_name(THD *thd, st_select_lex *parent_select,
}
bool Item_subselect::wrap_tvc_in_derived_table(THD *thd,
st_select_lex *tvc_sl)
{
LEX *lex= thd->lex;
/* SELECT_LEX object where the transformation is performed */
SELECT_LEX *parent_select= lex->current_select;
uint8 save_derived_tables= lex->derived_tables;
Query_arena backup;
Query_arena *arena= thd->activate_stmt_arena_if_needed(&backup);
/*
Create SELECT_LEX of the subquery SQ used in the result of transformation
*/
lex->current_select= tvc_sl;
if (mysql_new_select(lex, 0, NULL))
goto err;
mysql_init_select(lex);
/* Create item list as '*' for the subquery SQ */
Item *item;
SELECT_LEX *sq_select; // select for IN subquery;
sq_select= lex->current_select;
sq_select->linkage= tvc_sl->linkage;
sq_select->parsing_place= SELECT_LIST;
item= new (thd->mem_root) Item_field(thd, &sq_select->context,
NULL, NULL, &star_clex_str);
if (item == NULL || add_item_to_list(thd, item))
goto err;
(sq_select->with_wild)++;
/* Exclude SELECT with TVC */
tvc_sl->exclude();
/*
Create derived table DT that will wrap TVC in the result of transformation
*/
SELECT_LEX *tvc_select; // select for tvc
SELECT_LEX_UNIT *derived_unit; // unit for tvc_select
if (mysql_new_select(lex, 1, tvc_sl))
goto err;
tvc_select= lex->current_select;
derived_unit= tvc_select->master_unit();
tvc_select->linkage= DERIVED_TABLE_TYPE;
lex->current_select= sq_select;
/*
Create the name of the wrapping derived table and
add it to the FROM list of the subquery SQ
*/
Table_ident *ti;
LEX_CSTRING alias;
TABLE_LIST *derived_tab;
if (!(ti= new (thd->mem_root) Table_ident(derived_unit)) ||
create_tvc_name(thd, parent_select, &alias))
goto err;
if (!(derived_tab=
sq_select->add_table_to_list(thd,
ti, &alias, 0,
TL_READ, MDL_SHARED_READ)))
goto err;
sq_select->add_joined_table(derived_tab);
sq_select->add_where_field(derived_unit->first_select());
sq_select->context.table_list= sq_select->table_list.first;
sq_select->context.first_name_resolution_table= sq_select->table_list.first;
sq_select->table_list.first->derived_type= DTYPE_TABLE | DTYPE_MATERIALIZE;
lex->derived_tables|= DERIVED_SUBQUERY;
sq_select->where= 0;
sq_select->set_braces(false);
derived_unit->set_with_clause(0);
if (engine->engine_type() == subselect_engine::SINGLE_SELECT_ENGINE)
((subselect_single_select_engine *) engine)->change_select(sq_select);
if (arena)
thd->restore_active_arena(arena, &backup);
lex->current_select= sq_select;
return false;
err:
if (arena)
thd->restore_active_arena(arena, &backup);
lex->derived_tables= save_derived_tables;
lex->current_select= parent_select;
return true;
}
/**
@brief
Transform IN predicate into IN subquery
@ -532,6 +622,7 @@ Item *Item_func_in::in_predicate_to_in_subs_transformer(THD *thd,
if (!transform_into_subq)
return this;
transform_into_subq= false;
List<List_item> values;
@ -540,6 +631,12 @@ Item *Item_func_in::in_predicate_to_in_subs_transformer(THD *thd,
/* SELECT_LEX object where the transformation is performed */
SELECT_LEX *parent_select= lex->current_select;
uint8 save_derived_tables= lex->derived_tables;
for (uint i=1; i < arg_count; i++)
{
if (!args[i]->const_item())
return this;
}
Query_arena backup;
Query_arena *arena= thd->activate_stmt_arena_if_needed(&backup);