Details
Description
Data comes from Sandy Bridge system running sysbench OLTP RO in 1 thread against 1 table.
Call graphs:
- 0.26% mysqld mysqld
- Item_func::type() const
+ 18.31% JOIN::optimize_inner()
+ 17.94% MYSQLparse(THD*)
+ 11.70% update_ref_and_keys(THD*, st_dynamic_array*, st_join_table*, unsigned int, Item*, unsigned long long, st_select_lex*, st_sargable_param**) [clone .isra.253]
+ 10.26% build_equal_items(JOIN*, Item*, COND_EQUAL*, List<TABLE_LIST>*, bool, COND_EQUAL**, bool) [clone .constprop.262]
+ 6.81% internal_remove_eq_conds(THD*, Item*, Item::cond_result*)
+ 5.92% JOIN::prepare(Item***, TABLE_LIST*, unsigned int, Item*, unsigned int, st_order*, bool, st_order*, Item*, st_order*, st_select_lex*, st_select_lex_unit*)
+ 5.32% join_read_const_table(st_join_table*, st_position*) [clone .isra.248]
+ 4.84% JOIN::optimize()
+ 3.57% make_join_statistics(JOIN*, List<TABLE_LIST>&, st_dynamic_array*)
+ 3.01% SQL_SELECT::test_quick_select(THD*, Bitmap<64u>, unsigned long long, unsigned long long, bool, bool, bool)
+ 3.00% remove_eq_conds(THD*, Item*, Item::cond_result*)
+ 2.92% Item_func::compile(bool (Item::*)(unsigned char**), unsigned char**, Item* (Item::*)(unsigned char*), unsigned char*)
+ 2.52% Item_equal::add_const(Item*, Item*)
+ 2.01% Item_func::setup_args_and_comparator(THD*, Arg_comparator*)
+ 1.31% make_join_select(JOIN*, SQL_SELECT*, Item*)
This is virtual method which can't be inlined. Most time spent for function call convention. Check if we can revoke it's virtual status.
Gliffy Diagrams
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Issue Links
- is blocked by
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MDEV-8024 Remove excessive update_used_tables() calls
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- Closed
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Activity
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- Comments
- Work Log
- History
- Activity
- Transitions
Plan:
1. Fix "MDEV-8024 Remove excessive update_used_tables() calls".
Move the call for update_used_tables() from build_equal_items() to build_equal_items_for_cond().
2a. Introduce a new class Item_ident_or_func_or_sum, common parent for Item_func_or_sum and Item_ident (which covert Item_field and Item_ref), as they behave in very similar ways in the function build_equal_items_for_cond.
2b. Change the function build_equal_items_for_cond() into virtual method in Item and split the function into at least:
- Item::build_equal_items_for_cond()
- Item_cond::build_equal_items_for_cond()
- Item_cond_and::build_equal_items_for_cond()
- Item_ident_or_func_or_sum::build_equal_items_for_cond()
2c. Update: After discussion with Igor, it appeared that Item_field and Item_ref cannot appear in this context in the function build_equal_item_for_cond:
else if (cond->type() == Item::FUNC_ITEM || cond->real_item()->type() == Item::FIELD_ITEM)
because conditions of type:
WHERE/HAVING field
are already replaced to:
WHERE/HAVING field<>0
by the time of a build_eqial_items() call. See normilize_cond().
The part of the condition checking for Item_field::FIELD_ITEM was a dead code.
Therefore the implementation of Item_ident_or_func_or_sum::build_equal_items() can be moved to Item_func, and Item_ident_or_func_or_sum itself is not really needed.
3. Split the function check_equality() into a method in Item. Implement
Item::check_equality() and Item_func_eq::check_equality().
This will replace two virtual calls inside the former function check_equality():
if (item->type() == Item::FUNC_ITEM &&
((Item_func*) item)->functype() == Item_func::EQ_FUNC)
into a single virtual call in Item_cond_and::build_equal_items :
if (item->check_equality(thd, &cond_equal, &eq_list))
Additionally, implement Item_func_eq::build_equal_items() in addition to Item_func::build_equal_items() and move the call for check_equality() from Item_func::build_equal_items() to Item_func_eq::build_equal_items().
4. Change this piece of code in the function build_equal_items():
if (cond) { cond= build_equal_items_for_cond(thd, cond, 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)->cond_equal; else if (cond->type() == Item::FUNC_ITEM && ((Item_cond*) cond)->functype() == Item_func::MULT_EQUAL_FUNC) { cond_equal= new COND_EQUAL; cond_equal->current_level.push_back((Item_equal *) cond); } }
to get rid of virtual calls by adding a new out parameter to Item::build_equal_items() of type COND_EQUAL**:
virtual COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
bool link_item_fields,
COND_EQUAL **cond_equal_ref)
so Item::build_equal_items() can create cond_equal internally.
This will replace two virtual calls, type() followed by functype(), to a single virtual call for build_equal_cond().
5. Split the functions remove_eq_conds() and internal_remove_eq_conds() into a virtual method Item::remove_eq_conds(). This will replace about 6 calls for item->type() into a single call for item->remove_eq_conds().
6. Split the function add_key_fields() into a method in Item. This will remove about 3 virtual calls item->type(), as well as some virtual calls item_func->functype(), and will add one virtual call item->add_key_fields() instead.
7. Split the function get_mm_parts() into a virtual method in Item. This will replaces one virtual call item->type() to another virtual call, item->get_mm_tree(), but also will remove a virtual call for functype(), which used to distinguish between COND_AND_FUNC and COND_OR_FUNC:
if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
8. Split the code in Item::get_mm_tree() responsible for functions into methods in Item_func and its descendants:
- Item_func
- Item_func_between
- Item_func_in
- Item_equal
This will remove a virtual call:if (type() != Item::FUNC_ITEM)as well as remove virtual call checking functype():
switch (cond_func->functype()) { case Item_func::BETWEEN: ..
9. Add get_mm_tree() in Item_func_like, Item_rowready_func2, Item_func_spatial_rel to get rid of the select_optimize() and have_rev_func() virtual calls.
Remove virtual methods Item_func::select_optimize(), Item_func::have_rev_func(), as well as enum Item_func::optimize_type, because they won't be needed any more.
Item_func_type() calls that remain after step4 (14 calls)
#1 0x0000555555a1db8a in normalize_cond (cond=0x7fff3c005be8) #1 0x00005555559b4a93 in setup_conds (thd=0x55555a92e650, #1 0x0000555555c85637 in Arg_comparator::is_owner_equal_func ( #2 0x0000555555c73051 in Arg_comparator::set_compare_func ( #3 0x0000555555c73e7f in Arg_comparator::set_cmp_func (this=0x7fff3c005cb0, #4 0x0000555555a8bd84 in Arg_comparator::set_cmp_func (this=0x7fff3c005cb0, #5 0x0000555555c72f83 in Item_func::setup_args_and_comparator ( #6 0x0000555555c72ffb in Item_bool_func2::fix_length_and_dec ( #1 0x0000555555a6ca56 in propagate_cond_constants (thd=0x55555a92e650, #2 0x0000555555a6e365 in optimize_cond (join=0x7fff3c005e48, #3 0x0000555555a4a818 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a6f85f in remove_eq_conds (thd=0x55555a92e650, #2 0x0000555555a6e3b3 in optimize_cond (join=0x7fff3c005e48, #3 0x0000555555a4a818 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a6eabd in internal_remove_eq_conds (thd=0x55555a92e650, #2 0x0000555555a6fa56 in remove_eq_conds (thd=0x55555a92e650, #3 0x0000555555a6e3b3 in optimize_cond (join=0x7fff3c005e48, #4 0x0000555555a4a818 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a6e989 in cond_is_datetime_is_null (cond=0x7fff3c006968) #2 0x0000555555a6f457 in internal_remove_eq_conds (thd=0x55555a92e650, #3 0x0000555555a6fa56 in remove_eq_conds (thd=0x55555a92e650, #4 0x0000555555a6e3b3 in optimize_cond (join=0x7fff3c005e48, #5 0x0000555555a4a818 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a6e3d7 in optimize_cond (join=0x7fff3c005e48, #2 0x0000555555a4a818 in JOIN::optimize_inner (this=0x7fff3c005e48) #3 0x0000555555a49fe4 in JOIN::optimize (this=0x7fff3c005e48) #4 0x0000555555a5205a in mysql_select (thd=0x55555a92e650, #1 0x0000555555a55ff1 in add_key_fields (join=0x7fff3c005e48, #2 0x0000555555a5804b in update_ref_and_keys (thd=0x55555a92e650, #3 0x0000555555a5303a in make_join_statistics (join=0x7fff3c005e48, #4 0x0000555555a4b050 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a5624d in add_key_fields (join=0x7fff3c005e48, #2 0x0000555555a5804b in update_ref_and_keys (thd=0x55555a92e650, #3 0x0000555555a5303a in make_join_statistics (join=0x7fff3c005e48, #1 0x0000555555a56407 in add_key_fields (join=0x7fff3c005e48, #2 0x0000555555a5804b in update_ref_and_keys (thd=0x55555a92e650, #3 0x0000555555a5303a in make_join_statistics (join=0x7fff3c005e48, #4 0x0000555555a4b050 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a6f85f in remove_eq_conds (thd=0x55555a92e650, #2 0x0000555555a53f78 in make_join_statistics (join=0x7fff3c005e48, #3 0x0000555555a4b050 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a6eabd in internal_remove_eq_conds (thd=0x55555a92e650, #2 0x0000555555a6fa56 in remove_eq_conds (thd=0x55555a92e650, #3 0x0000555555a53f78 in make_join_statistics (join=0x7fff3c005e48, #4 0x0000555555a4b050 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a6e989 in cond_is_datetime_is_null (cond=0x7fff3c006968) #2 0x0000555555a6f457 in internal_remove_eq_conds (thd=0x55555a92e650, #3 0x0000555555a6fa56 in remove_eq_conds (thd=0x55555a92e650, #4 0x0000555555a53f78 in make_join_statistics (join=0x7fff3c005e48, #5 0x0000555555a4b050 in JOIN::optimize_inner (this=0x7fff3c005e48)
Item_func_type() calls that remain after step#5 (8 calls)
#1 0x0000555555a1db8a in normalize_cond (cond=0x7fff3c005be8) #1 0x00005555559b4a93 in setup_conds (thd=0x55555a92e650, #1 0x0000555555c85637 in Arg_comparator::is_owner_equal_func ( #2 0x0000555555c73051 in Arg_comparator::set_compare_func ( #3 0x0000555555c73e7f in Arg_comparator::set_cmp_func (this=0x7fff3c005cb0, #4 0x0000555555a8bd84 in Arg_comparator::set_cmp_func (this=0x7fff3c005cb0, #5 0x0000555555c72f83 in Item_func::setup_args_and_comparator ( #6 0x0000555555c72ffb in Item_bool_func2::fix_length_and_dec ( #1 0x0000555555a6ca56 in propagate_cond_constants (thd=0x55555a92e650, #2 0x0000555555a6e365 in optimize_cond (join=0x7fff3c005e48, #3 0x0000555555a4a818 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a6e3d7 in optimize_cond (join=0x7fff3c005e48, #2 0x0000555555a4a818 in JOIN::optimize_inner (this=0x7fff3c005e48) #3 0x0000555555a49fe4 in JOIN::optimize (this=0x7fff3c005e48) #4 0x0000555555a5205a in mysql_select (thd=0x55555a92e650, #1 0x0000555555a55ff1 in add_key_fields (join=0x7fff3c005e48, #2 0x0000555555a5804b in update_ref_and_keys (thd=0x55555a92e650, #3 0x0000555555a5303a in make_join_statistics (join=0x7fff3c005e48, #4 0x0000555555a4b050 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a5624d in add_key_fields (join=0x7fff3c005e48, #2 0x0000555555a5804b in update_ref_and_keys (thd=0x55555a92e650, #3 0x0000555555a5303a in make_join_statistics (join=0x7fff3c005e48, #1 0x0000555555a56407 in add_key_fields (join=0x7fff3c005e48, #2 0x0000555555a5804b in update_ref_and_keys (thd=0x55555a92e650, #3 0x0000555555a5303a in make_join_statistics (join=0x7fff3c005e48, #4 0x0000555555a4b050 in JOIN::optimize_inner (this=0x7fff3c005e48)
Item_func_type() calls that remain after step#6 (5 calls)
#1 0x0000555555a1db8a in normalize_cond (cond=0x7fff3c005be8) #2 0x0000555555bc8ed0 in MYSQLparse (thd=0x555557f5c360) #1 0x00005555559b4a93 in setup_conds (thd=0x55555a92e650, #1 0x0000555555c85637 in Arg_comparator::is_owner_equal_func ( #2 0x0000555555c73051 in Arg_comparator::set_compare_func ( #3 0x0000555555c73e7f in Arg_comparator::set_cmp_func (this=0x7fff3c005cb0, #4 0x0000555555a8bd84 in Arg_comparator::set_cmp_func (this=0x7fff3c005cb0, #5 0x0000555555c72f83 in Item_func::setup_args_and_comparator ( #6 0x0000555555c72ffb in Item_bool_func2::fix_length_and_dec ( #1 0x0000555555a6ca56 in propagate_cond_constants (thd=0x55555a92e650, #2 0x0000555555a6e365 in optimize_cond (join=0x7fff3c005e48, #3 0x0000555555a4a818 in JOIN::optimize_inner (this=0x7fff3c005e48) #1 0x0000555555a6e3d7 in optimize_cond (join=0x7fff3c005e48, #2 0x0000555555a4a818 in JOIN::optimize_inner (this=0x7fff3c005e48) #3 0x0000555555a49fe4 in JOIN::optimize (this=0x7fff3c005e48) #4 0x0000555555a5205a in mysql_select (thd=0x55555a92e650,
In this SQL script:
Item_func::type() is called 16 times from JOIN::optimizer() and its callees during the above SELECT query: