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Message #08565
Re: Step#4: MDEV-7950 Item_func::type() takes 0.26% in OLTP RO
Hi Sergey,
I'm sending a new version, which takes into account your review
suggestions and our skype discussion.
Thanks.
On 05/08/2015 12:27 PM, Sergey Vojtovich wrote:
Hi Alexander,
following profiler reports for build_equal_items* in your and mine patches.
For OLTP RO they're equal. I guess Item_func::build_equal_items() was not
inlined due to recursion?
Bar's patch
-----------
0.06% Item_func_eq::build_equal_items_and_cond()
0.05% build_equal_items()
0.01% Item_func::build_equal_items()
0.00% Item_func::build_equal_items_and_cond()
Svoj's patch
------------
0.06% build_equal_items()
0.05% Item_func_eq::build_equal_items_and_cond()
0.01% Item_func::build_equal_items()
0.00% Item::build_equal_items_and_cond()
Regards,
Sergey
On Thu, May 07, 2015 at 01:58:28PM +0400, Sergey Vojtovich wrote:
Hi Alexander,
comments inline.
On Wed, May 06, 2015 at 07:51:18PM +0400, Alexander Barkov wrote:
Hi Sergey,
Please review a patch for the next step for MDEV-7950
(one small thing at a time, to avoid huge unclear patches)
Thanks.
diff --git a/sql/item.h b/sql/item.h
index 043605a..a665d23 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -1133,6 +1133,13 @@ class Item: public Type_std_attributes
update_used_tables();
return this;
}
+ virtual COND *build_equal_items_and_cond(THD *thd, COND_EQUAL *inherited,
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
+ {
+ *cond_equal_ref= NULL;
+ return Item::build_equal_items(thd, inherited, link_item_fields);
+ }
/*
Checks whether the item is:
- a simple equality (field=field_item or field=constant_item), or
cond_equal_ref is initialized to 0 by caller, why duplicate initialization here
and everywhere else?
When you write XXX::build_equal_items() you force static call indeed, but not
inlining, which we're aiming for. That is non-inlined static call as such won't
save us much compared to virtual call.
I think our aim should be to keep build_equal_items_and_cond() virtual and have
build_equal_items() inlined into the former. So we mostly rely on compiler's
optimizer.
I _believe_ it should be clever enough to optimize the following as described
above:
class Item
{
...
virtual build_equal_items_and_cond()
{ return build_equal_items(); }
...
}
This should be easy to test by adding "inline" to build_equal_items()
declaration and compiling with -Winline.
Makes sense?
...skip...
index 53f249d..0c279ed 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -1989,6 +2002,11 @@ class COND_EQUAL: public Sql_alloc
{
upper_levels= 0;
}
+ COND_EQUAL(Item_equal *item_equal)
+ :upper_levels(0)
+ {
+ current_level.push_back(item_equal);
+ }
void copy(COND_EQUAL &cond_equal)
{
max_members= cond_equal.max_members;
If possible, here and everywhere else please use
push_back(item_equal, thd->mem_root). This will save us one
pthread_getspecific() call.
@@ -1998,6 +2016,8 @@ class COND_EQUAL: public Sql_alloc
else
current_level= cond_equal.current_level;
}
+ Item_equal *build_item_equal_from_current_level(THD *thd,
+ COND_EQUAL *inherited);
};
@@ -2106,8 +2126,23 @@ class Item_cond_and :public Item_cond
void mark_as_condition_AND_part(TABLE_LIST *embedding);
virtual uint exists2in_reserved_items() { return list.elements; };
bool walk_top_and(Item_processor processor, uchar *arg);
+ void build_new_level(THD *thd, COND_EQUAL *cond_equal);
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
bool link_item_fields);
Didn't get the need for build_item_equal_from_current_level() and
build_new_level(). Is it just some minor refactoring?
...skip...
diff --git a/sql/item_func.h b/sql/item_func.h
index 0d57c2b..01e1527 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -133,6 +133,15 @@ class Item_func :public Item_func_or_sum, public Used_tables_and_const_cache
}
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
bool link_item_fields);
+ COND *build_equal_items_and_cond(THD *thd, COND_EQUAL *inherited,
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
+ {
+ *cond_equal_ref= NULL;
+ COND *cond= build_equal_items(thd, inherited, link_item_fields);
+ DBUG_ASSERT(cond == this);
+ return cond;
+ }
bool eq(const Item *item, bool binary_cmp) const;
virtual optimize_type select_optimize() const { return OPTIMIZE_NONE; }
virtual bool have_rev_func() const { return 0; }
The only difference from base build_equal_items_and_cond() is just DBUG_ASSERT().
I think assert can be moved into base implementation with more complex condition
too (assuming we'll decide to keep only base implementation).
...skip...
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 95778f0..7658a24 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -13053,23 +13127,14 @@ static COND *build_equal_items(JOIN *join, COND *cond,
if (cond)
{
- cond= cond->build_equal_items(thd, inherited, link_equal_fields);
- if (cond->type() == Item::COND_ITEM &&
- ((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
- cond_equal= &((Item_cond_and*) cond)->m_cond_equal;
-
- else if (cond->type() == Item::FUNC_ITEM &&
- ((Item_cond*) cond)->functype() == Item_func::MULT_EQUAL_FUNC)
+ cond= cond->build_equal_items_and_cond(thd, inherited, link_equal_fields,
+ &cond_equal);
+ if (cond_equal)
{
- cond_equal= new COND_EQUAL;
- cond_equal->current_level.push_back((Item_equal *) cond);
+ cond_equal->upper_levels= inherited;
+ inherited= cond_equal;
}
}
- if (cond_equal)
- {
- cond_equal->upper_levels= inherited;
- inherited= cond_equal;
- }
*cond_equal_ref= cond_equal;
if (join_list && !ignore_on_conds)
I believe this *cond_equal_ref= cond_equal is probably not needed. Initialize
cond_equal_ref directly and remove cond_equal variable.
Regards,
Sergey
diff --git a/sql/item.h b/sql/item.h
index 043605a..017d348 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -1128,9 +1128,11 @@ class Item: public Type_std_attributes
void print_value(String *);
virtual void update_used_tables() {}
virtual COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
- bool link_item_fields)
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
{
update_used_tables();
+ DBUG_ASSERT(!cond_equal_ref || !cond_equal_ref[0]);
return this;
}
/*
@@ -2335,7 +2337,8 @@ class Item_field :public Item_ident
update_table_bitmaps();
}
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
- bool link_item_fields)
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
{
/*
normilize_cond() replaced all conditions of type
@@ -2351,7 +2354,8 @@ class Item_field :public Item_ident
SELECT * FROM t1 WHERE DEFAULT(a);
*/
DBUG_ASSERT(type() != FIELD_ITEM);
- return Item_ident::build_equal_items(thd, inherited, link_item_fields);
+ return Item_ident::build_equal_items(thd, inherited, link_item_fields,
+ cond_equal_ref);
}
bool is_result_field() { return false; }
void set_result_field(Field *field) {}
@@ -3593,7 +3597,8 @@ class Item_ref :public Item_ident
table_map used_tables() const;
void update_used_tables();
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
- bool link_item_fields)
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
{
/*
normilize_cond() replaced all conditions of type
@@ -3604,7 +3609,8 @@ class Item_ref :public Item_ident
already be replaced. No Item_ref referencing to Item_field are possible.
*/
DBUG_ASSERT(real_type() != FIELD_ITEM);
- return Item_ident::build_equal_items(thd, inherited, link_item_fields);
+ return Item_ident::build_equal_items(thd, inherited, link_item_fields,
+ cond_equal_ref);
}
bool const_item() const
{
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index 53f249d..0a3bf41 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -563,7 +563,8 @@ class Item_func_eq :public Item_bool_rowready_func2
const char *func_name() const { return "="; }
Item *negated_item();
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
- bool link_item_fields);
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref);
bool check_equality(THD *thd, COND_EQUAL *cond, List<Item> *eq_list);
/*
- If this equality is created from the subquery's IN-equality:
@@ -1772,7 +1773,8 @@ class Item_cond :public Item_bool_func
used_tables_and_const_cache_update_and_join(list);
}
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
- bool link_item_fields);
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref);
virtual void print(String *str, enum_query_type query_type);
void split_sum_func(THD *thd, Item **ref_pointer_array, List<Item> &fields);
friend int setup_conds(THD *thd, TABLE_LIST *tables, TABLE_LIST *leaves,
@@ -1960,6 +1962,9 @@ class Item_equal: public Item_bool_func
void fix_length_and_dec();
bool fix_fields(THD *thd, Item **ref);
void update_used_tables();
+ COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref);
bool walk(Item_processor processor, bool walk_subquery, uchar *arg);
Item *transform(Item_transformer transformer, uchar *arg);
virtual void print(String *str, enum_query_type query_type);
@@ -1989,6 +1994,11 @@ class COND_EQUAL: public Sql_alloc
{
upper_levels= 0;
}
+ COND_EQUAL(Item_equal *item, MEM_ROOT *mem_root)
+ :upper_levels(0)
+ {
+ current_level.push_back(item, mem_root);
+ }
void copy(COND_EQUAL &cond_equal)
{
max_members= cond_equal.max_members;
@@ -2107,7 +2117,8 @@ class Item_cond_and :public Item_cond
virtual uint exists2in_reserved_items() { return list.elements; };
bool walk_top_and(Item_processor processor, uchar *arg);
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
- bool link_item_fields);
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref);
};
inline bool is_cond_and(Item *item)
diff --git a/sql/item_func.h b/sql/item_func.h
index 0d57c2b..a5ddb24 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -132,7 +132,8 @@ class Item_func :public Item_func_or_sum, public Used_tables_and_const_cache
used_tables_and_const_cache_update_and_join(arg_count, args);
}
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
- bool link_item_fields);
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref);
bool eq(const Item *item, bool binary_cmp) const;
virtual optimize_type select_optimize() const { return OPTIMIZE_NONE; }
virtual bool have_rev_func() const { return 0; }
diff --git a/sql/item_sum.h b/sql/item_sum.h
index b540b44..056c623 100644
--- a/sql/item_sum.h
+++ b/sql/item_sum.h
@@ -445,7 +445,8 @@ class Item_sum :public Item_func_or_sum
table_map used_tables() const { return used_tables_cache; }
void update_used_tables ();
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
- bool link_item_fields)
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
{
/*
Item_sum (and derivants) of the original WHERE/HAVING clauses
@@ -453,7 +454,8 @@ class Item_sum :public Item_func_or_sum
build_equal_items() is called. See Item::split_sum_func2().
*/
DBUG_ASSERT(0);
- return Item::build_equal_items(thd, inherited, link_item_fields);
+ return Item::build_equal_items(thd, inherited, link_item_fields,
+ cond_equal_ref);
}
bool is_null() { return null_value; }
void make_const ()
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 95778f0..2cc0173 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -12773,7 +12773,8 @@ bool Item_func_eq::check_equality(THD *thd, COND_EQUAL *cond_equal,
COND *Item_cond_and::build_equal_items(THD *thd,
COND_EQUAL *inherited,
- bool link_item_fields)
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
{
Item_equal *item_equal;
COND_EQUAL cond_equal;
@@ -12785,6 +12786,7 @@ COND *Item_cond_and::build_equal_items(THD *thd,
List_iterator<Item> li(*args);
Item *item;
+ DBUG_ASSERT(!cond_equal_ref || !cond_equal_ref[0]);
/*
Retrieve all conjuncts of this level detecting the equality
that are subject to substitution by multiple equality items and
@@ -12809,7 +12811,7 @@ COND *Item_cond_and::build_equal_items(THD *thd,
if (!args->elements &&
!cond_equal.current_level.elements &&
!eq_list.elements)
- return new Item_int((longlong) 1, 1);
+ return new (thd->mem_root) Item_int((longlong) 1, 1);
List_iterator_fast<Item_equal> it(cond_equal.current_level);
while ((item_equal= it++))
@@ -12833,7 +12835,7 @@ COND *Item_cond_and::build_equal_items(THD *thd,
while ((item= li++))
{
Item *new_item;
- if ((new_item= item->build_equal_items(thd, inherited, FALSE))
+ if ((new_item= item->build_equal_items(thd, inherited, false, NULL))
!= item)
{
/* This replacement happens only for standalone equalities */
@@ -12848,19 +12850,23 @@ COND *Item_cond_and::build_equal_items(THD *thd,
args->append(&eq_list);
args->append((List<Item> *)&cond_equal.current_level);
update_used_tables();
+ if (cond_equal_ref)
+ *cond_equal_ref= &m_cond_equal;
return this;
}
COND *Item_cond::build_equal_items(THD *thd,
COND_EQUAL *inherited,
- bool link_item_fields)
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
{
List<Item> *args= argument_list();
List_iterator<Item> li(*args);
Item *item;
+ DBUG_ASSERT(!cond_equal_ref || !cond_equal_ref[0]);
/*
Make replacement of equality predicates for lower levels
of the condition expression.
@@ -12870,7 +12876,7 @@ COND *Item_cond::build_equal_items(THD *thd,
while ((item= li++))
{
Item *new_item;
- if ((new_item= item->build_equal_items(thd, inherited, FALSE))
+ if ((new_item= item->build_equal_items(thd, inherited, false, NULL))
!= item)
{
/* This replacement happens only for standalone equalities */
@@ -12889,11 +12895,14 @@ COND *Item_cond::build_equal_items(THD *thd,
COND *Item_func_eq::build_equal_items(THD *thd,
COND_EQUAL *inherited,
- bool link_item_fields)
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
{
COND_EQUAL cond_equal;
cond_equal.upper_levels= inherited;
List<Item> eq_list;
+
+ DBUG_ASSERT(!cond_equal_ref || !cond_equal_ref[0]);
/*
If an equality predicate forms the whole and level,
we call it standalone equality and it's processed here.
@@ -12909,7 +12918,7 @@ COND *Item_func_eq::build_equal_items(THD *thd,
Item_equal *item_equal;
int n= cond_equal.current_level.elements + eq_list.elements;
if (n == 0)
- return new Item_int((longlong) 1,1);
+ return new (thd->mem_root) Item_int((longlong) 1,1);
else if (n == 1)
{
if ((item_equal= cond_equal.current_level.pop()))
@@ -12919,10 +12928,14 @@ COND *Item_func_eq::build_equal_items(THD *thd,
set_if_bigger(thd->lex->current_select->max_equal_elems,
item_equal->n_field_items());
item_equal->upper_levels= inherited;
+ if (cond_equal_ref)
+ *cond_equal_ref= new (thd->mem_root) COND_EQUAL(item_equal,
+ thd->mem_root);
return item_equal;
}
Item *res= eq_list.pop();
res->update_used_tables();
+ DBUG_ASSERT(res->type() == FUNC_ITEM);
return res;
}
else
@@ -12946,15 +12959,19 @@ COND *Item_func_eq::build_equal_items(THD *thd,
cond_equal.current_level= and_cond->m_cond_equal.current_level;
args->append((List<Item> *)&cond_equal.current_level);
and_cond->update_used_tables();
+ if (cond_equal_ref)
+ *cond_equal_ref= &and_cond->m_cond_equal;
return and_cond;
}
}
- return Item_func::build_equal_items(thd, inherited, link_item_fields);
+ return Item_func::build_equal_items(thd, inherited, link_item_fields,
+ cond_equal_ref);
}
COND *Item_func::build_equal_items(THD *thd, COND_EQUAL *inherited,
- bool link_item_fields)
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
{
/*
For each field reference in cond, not from equal item predicates,
@@ -12968,6 +12985,20 @@ COND *Item_func::build_equal_items(THD *thd, COND_EQUAL *inherited,
&Item::equal_fields_propagator,
(uchar *) inherited);
cond->update_used_tables();
+ DBUG_ASSERT(cond == this);
+ DBUG_ASSERT(!cond_equal_ref || !cond_equal_ref[0]);
+ return cond;
+}
+
+
+COND *Item_equal::build_equal_items(THD *thd, COND_EQUAL *inherited,
+ bool link_item_fields,
+ COND_EQUAL **cond_equal_ref)
+{
+ COND *cond= Item_func::build_equal_items(thd, inherited, link_item_fields,
+ cond_equal_ref);
+ if (cond_equal_ref)
+ *cond_equal_ref= new (thd->mem_root) COND_EQUAL(this, thd->mem_root);
return cond;
}
@@ -13049,28 +13080,19 @@ static COND *build_equal_items(JOIN *join, COND *cond,
bool link_equal_fields)
{
THD *thd= join->thd;
- COND_EQUAL *cond_equal= 0;
+
+ *cond_equal_ref= NULL;
if (cond)
{
- cond= cond->build_equal_items(thd, inherited, link_equal_fields);
- if (cond->type() == Item::COND_ITEM &&
- ((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
- cond_equal= &((Item_cond_and*) cond)->m_cond_equal;
-
- else if (cond->type() == Item::FUNC_ITEM &&
- ((Item_cond*) cond)->functype() == Item_func::MULT_EQUAL_FUNC)
+ cond= cond->build_equal_items(thd, inherited, link_equal_fields,
+ cond_equal_ref);
+ if (*cond_equal_ref)
{
- cond_equal= new COND_EQUAL;
- cond_equal->current_level.push_back((Item_equal *) cond);
+ (*cond_equal_ref)->upper_levels= inherited;
+ inherited= *cond_equal_ref;
}
}
- if (cond_equal)
- {
- cond_equal->upper_levels= inherited;
- inherited= cond_equal;
- }
- *cond_equal_ref= cond_equal;
if (join_list && !ignore_on_conds)
{
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