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MDEV-8024 Remove excessive update_used_tables() calls

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This commit is contained in:
Alexander Barkov
2015-04-22 12:40:23 +04:00
parent e7a7ea7ec1
commit fc1f301e91
12 changed files with 156 additions and 127 deletions
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37
sql/sql_select.cc
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@ -12770,7 +12770,9 @@ static bool check_equality(THD *thd, Item *item, COND_EQUAL *cond_equal,
@param inherited path to all inherited multiple equality items
@return
pointer to the transformed condition
pointer to the transformed condition,
whose Used_tables_and_const_cache is up to date,
so no additional update_used_tables() is needed on the result.
*/
static COND *build_equal_items_for_cond(THD *thd, COND *cond,
@ -12784,9 +12786,9 @@ static COND *build_equal_items_for_cond(THD *thd, COND *cond,
if (cond->type() == Item::COND_ITEM)
{
List<Item> eq_list;
bool and_level= ((Item_cond*) cond)->functype() ==
Item_func::COND_AND_FUNC;
List<Item> *args= ((Item_cond*) cond)->argument_list();
Item_cond *cond_item= (Item_cond*) cond;
bool and_level= cond_item->functype() == Item_func::COND_AND_FUNC;
List<Item> *args= cond_item->argument_list();
List_iterator<Item> li(*args);
Item *item;
@ -12837,8 +12839,10 @@ static COND *build_equal_items_for_cond(THD *thd, COND *cond,
/*
Make replacement of equality predicates for lower levels
of the condition expression.
Update used_tables_cache and const_item_cache on the way.
*/
li.rewind();
cond_item->used_tables_and_const_cache_init();
while ((item= li++))
{
Item *new_item;
@ -12853,12 +12857,27 @@ static COND *build_equal_items_for_cond(THD *thd, COND *cond,
*/
li.replace(new_item);
}
cond_item->used_tables_and_const_cache_join(new_item);
}
if (and_level)
{
args->append(&eq_list);
args->append((List<Item> *)&cond_equal.current_level);
/*
Instead of the cond_item->update_used_tables() call below,
we could do this:
cond_item->used_tables_and_const_cache_update_and_join(eq_list);
cond_item->used_tables_and_const_cache_update_and_join(
*(List<Item> *) &cond_equal.current_level);
But initializing 2 iterators will probably be even slower than
redundant iterations over the topmost elements in "args",
which were already processed in the "while" loop above.
*/
cond_item->update_used_tables();
}
return cond_item;
}
else if (cond->type() == Item::FUNC_ITEM ||
cond->real_item()->type() == Item::FIELD_ITEM)
@ -12890,8 +12909,9 @@ static COND *build_equal_items_for_cond(THD *thd, COND *cond,
item_equal->upper_levels= inherited;
return item_equal;
}
return eq_list.pop();
Item *res= eq_list.pop();
res->update_used_tables();
return res;
}
else
{
@ -12913,7 +12933,7 @@ static COND *build_equal_items_for_cond(THD *thd, COND *cond,
and_cond->cond_equal.copy(cond_equal);
cond_equal.current_level= and_cond->cond_equal.current_level;
args->append((List<Item> *)&cond_equal.current_level);
and_cond->update_used_tables();
return and_cond;
}
}
@ -12928,8 +12948,8 @@ static COND *build_equal_items_for_cond(THD *thd, COND *cond,
&is_subst_valid,
&Item::equal_fields_propagator,
(uchar *) inherited);
cond->update_used_tables();
}
cond->update_used_tables();
return cond;
}
@ -13016,7 +13036,6 @@ static COND *build_equal_items(JOIN *join, COND *cond,
if (cond)
{
cond= build_equal_items_for_cond(thd, cond, inherited, link_equal_fields);
cond->update_used_tables();
if (cond->type() == Item::COND_ITEM &&
((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
cond_equal= &((Item_cond_and*) cond)->cond_equal;