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Merge bb-10.2-ext into 10.3

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Marko Mäkelä
2017-11-30 08:16:37 +02:00
parent 51b30586ea 5b697c5a23
commit 7cb3520c06
2034 changed files with 179230 additions and 109759 deletions
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33
sql/sql_select.cc
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@ -12857,7 +12857,7 @@ remove_const(JOIN *join,ORDER *first_order, COND *cond,
*simple_order=0; // Must do a temp table to sort
else if (!(order_tables & not_const_tables))
{
if (order->item[0]->has_subquery())
if (order->item[0]->with_subquery())
{
/*
Delay the evaluation of constant ORDER and/or GROUP expressions that
@ -12895,8 +12895,37 @@ remove_const(JOIN *join,ORDER *first_order, COND *cond,
can be used without tmp. table.
*/
bool can_subst_to_first_table= false;
bool first_is_in_sjm_nest= false;
if (first_is_base_table)
{
TABLE_LIST *tbl_for_first=
join->join_tab[join->const_tables].table->pos_in_table_list;
first_is_in_sjm_nest= tbl_for_first->sj_mat_info &&
tbl_for_first->sj_mat_info->is_used;
}
/*
Currently we do not employ the optimization that uses multiple
equalities for ORDER BY to remove tmp table in the case when
the first table happens to be the result of materialization of
a semi-join nest ( <=> first_is_in_sjm_nest == true).
When a semi-join nest is materialized and scanned to look for
possible matches in the remaining tables for every its row
the fields from the result of materialization are copied
into the record buffers of tables from the semi-join nest.
So these copies are used to access the remaining tables rather
than the fields from the result of materialization.
Unfortunately now this so-called 'copy back' technique is
supported only if the rows are scanned with the rr_sequential
function, but not with other rr_* functions that are employed
when the result of materialization is required to be sorted.
TODO: either to support 'copy back' technique for the above case,
or to get rid of this technique altogether.
*/
if (optimizer_flag(join->thd, OPTIMIZER_SWITCH_ORDERBY_EQ_PROP) &&
first_is_base_table &&
first_is_base_table && !first_is_in_sjm_nest &&
order->item[0]->real_item()->type() == Item::FIELD_ITEM &&
join->cond_equal)
{