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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. See also THD::emb_on_expr_nest.
*/ */
TABLE_LIST *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 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 materialization. Currently, we set this to FALSE when it as well could
@ -403,6 +397,18 @@ public:
*/ */
bool is_flattenable_semijoin; 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) bool *get_cond_guard(int i)
{ {
return pushed_cond_guards ? pushed_cond_guards + i : NULL; return pushed_cond_guards ? pushed_cond_guards + i : NULL;

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)? Item **tree= ((*in_subq)->emb_on_expr_nest == NO_JOIN_NEST)?
&join->conds : &((*in_subq)->emb_on_expr_nest->on_expr); &join->conds : &((*in_subq)->emb_on_expr_nest->on_expr);
Item *replace_me= *in_subq; Item *replace_me= (*in_subq)->original_item();
/*
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;
}
if (replace_where_subcondition(join, tree, replace_me, new Item_int(1), if (replace_where_subcondition(join, tree, replace_me, new Item_int(1),
FALSE)) FALSE))
DBUG_RETURN(TRUE); /* purecov: inspected */ DBUG_RETURN(TRUE); /* purecov: inspected */
@ -756,18 +747,7 @@ skip_conversion:
bool do_fix_fields= !(*in_subq)->substitution->fixed; bool do_fix_fields= !(*in_subq)->substitution->fixed;
Item **tree= ((*in_subq)->emb_on_expr_nest == NO_JOIN_NEST)? Item **tree= ((*in_subq)->emb_on_expr_nest == NO_JOIN_NEST)?
&join->conds : &((*in_subq)->emb_on_expr_nest->on_expr); &join->conds : &((*in_subq)->emb_on_expr_nest->on_expr);
Item *replace_me= (*in_subq)->original_item();
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;
}
if (replace_where_subcondition(join, tree, replace_me, substitute, if (replace_where_subcondition(join, tree, replace_me, substitute,
do_fix_fields)) do_fix_fields))
DBUG_RETURN(TRUE); DBUG_RETURN(TRUE);