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MWL#90: Address review feedback part #18

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This commit is contained in:
Sergey Petrunya 2011-04-05 12:20:03 +04:00
parent 409902f884
commit 151207134b
2 changed files with 14 additions and 28 deletions
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18
sql/item_subselect.h
View File

@ -371,12 +371,6 @@ public:
See also THD::emb_on_expr_nest.
*/
TABLE_LIST *emb_on_expr_nest;
/*
Location of the subquery predicate. It is either
- pointer to join nest if the subquery predicate is in the ON expression
- (TABLE_LIST*)1 if the predicate is in the WHERE.
*/
//TABLE_LIST *expr_join_nest;
/*
Types of left_expr and subquery's select list allow to perform subquery
materialization. Currently, we set this to FALSE when it as well could
@ -402,6 +396,18 @@ public:
TRUE<=>this is a flattenable semi-join, false overwise.
*/
bool is_flattenable_semijoin;
/*
Used to determine how this subselect item is represented in the item tree,
in case there is a need to locate it there and replace with something else.
Two options are possible:
1. This item is there 'as-is'.
1. This item is wrapped within Item_in_optimizer.
*/
Item *original_item()
{
return is_flattenable_semijoin ? (Item*)this : (Item*)optimizer;
}
bool *get_cond_guard(int i)
{

24
sql/opt_subselect.cc
View File

@ -712,16 +712,7 @@ bool convert_join_subqueries_to_semijoins(JOIN *join)
{
Item **tree= ((*in_subq)->emb_on_expr_nest == NO_JOIN_NEST)?
&join->conds : &((*in_subq)->emb_on_expr_nest->on_expr);
Item *replace_me= *in_subq;
/*
JTBM: the subquery was already mapped with Item_in_optimizer, so we
should search for that, not for original Item_in_subselect.
TODO: what about delaying that rewrite until here?
*/
if (!(*in_subq)->is_flattenable_semijoin)
{
replace_me= (*in_subq)->optimizer;
}
Item *replace_me= (*in_subq)->original_item();
if (replace_where_subcondition(join, tree, replace_me, new Item_int(1),
FALSE))
DBUG_RETURN(TRUE); /* purecov: inspected */
@ -756,18 +747,7 @@ skip_conversion:
bool do_fix_fields= !(*in_subq)->substitution->fixed;
Item **tree= ((*in_subq)->emb_on_expr_nest == NO_JOIN_NEST)?
&join->conds : &((*in_subq)->emb_on_expr_nest->on_expr);
Item *replace_me= *in_subq;
/*
JTBM: the subquery was already mapped with Item_in_optimizer, so we
should search for that, not for original Item_in_subselect.
TODO: what about delaying that rewrite until here?
*/
if (!(*in_subq)->is_flattenable_semijoin)
{
replace_me= (*in_subq)->optimizer;
}
Item *replace_me= (*in_subq)->original_item();
if (replace_where_subcondition(join, tree, replace_me, substitute,
do_fix_fields))
DBUG_RETURN(TRUE);