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MDEV-8199 - first_breadth_first_tab() takes 0.07% in OLTP RO

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Split first_breadth_first_tab() into
JOIN::first_breadth_first_optimization_tab() and
JOIN::first_breadth_first_execution_tab().

This allows to eliminate function call and one condition. Adjusted callers
accordingly.

Overhead change:
first_breadth_first_tab()        0.07% -> out of radar
next_breadth_first_tab()         0.04% -> 0.04%
JOIN::cleanup()                  0.15% -> 0.11%
JOIN::save_explain_data_intern() 0.28% -> 0.24%
This commit is contained in:
Sergey Vojtovich 2015-05-21 12:30:41 +04:00
parent 84568c2965
commit 45f41b52e8
2 changed files with 29 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

61
sql/sql_select.cc
View File

@ -277,7 +277,6 @@ JOIN_TAB *first_depth_first_tab(JOIN* join);
JOIN_TAB *next_depth_first_tab(JOIN* join, JOIN_TAB* tab);
enum enum_exec_or_opt {WALK_OPTIMIZATION_TABS , WALK_EXECUTION_TABS};
JOIN_TAB *first_breadth_first_tab(JOIN *join, enum enum_exec_or_opt tabs_kind);
JOIN_TAB *next_breadth_first_tab(JOIN *join, enum enum_exec_or_opt tabs_kind,
JOIN_TAB *tab);
static double table_cond_selectivity(JOIN *join, uint idx, JOIN_TAB *s,
@ -7202,7 +7201,7 @@ double JOIN::get_examined_rows()
{
double examined_rows;
double prev_fanout= 1;
JOIN_TAB *tab= first_breadth_first_tab(this, WALK_OPTIMIZATION_TABS);
JOIN_TAB *tab= first_breadth_first_optimization_tab();
JOIN_TAB *prev_tab= tab;
examined_rows= tab->get_examined_rows();
@ -8201,21 +8200,23 @@ prev_record_reads(POSITION *positions, uint idx, table_map found_ref)
Enumerate join tabs in breadth-first fashion, including const tables.
*/
JOIN_TAB *first_breadth_first_tab(JOIN *join, enum enum_exec_or_opt tabs_kind)
{
/* There's always one (i.e. first) table */
return (tabs_kind == WALK_EXECUTION_TABS)? join->join_tab:
join->table_access_tabs;
}
JOIN_TAB *next_breadth_first_tab(JOIN *join, enum enum_exec_or_opt tabs_kind,
JOIN_TAB *tab)
{
JOIN_TAB* const first_top_tab= first_breadth_first_tab(join, tabs_kind);
const uint n_top_tabs_count= (tabs_kind == WALK_EXECUTION_TABS)?
join->top_join_tab_count:
join->top_table_access_tabs_count;
JOIN_TAB *first_top_tab;
uint n_top_tabs_count;
if (tabs_kind == WALK_EXECUTION_TABS)
{
first_top_tab= join->first_breadth_first_execution_tab();
n_top_tabs_count= join->top_join_tab_count;
}
else
{
first_top_tab= join->first_breadth_first_optimization_tab();
n_top_tabs_count= join->top_table_access_tabs_count;
}
if (!tab->bush_root_tab)
{
/* We're at top level. Get the next top-level tab */
@ -11800,27 +11801,19 @@ void JOIN::cleanup(bool full)
w/o tables: they don't have some members initialized and
WALK_OPTIMIZATION_TABS may not work correctly for them.
*/
enum enum_exec_or_opt tabs_kind;
if (first_breadth_first_tab(this, WALK_OPTIMIZATION_TABS))
tabs_kind= WALK_OPTIMIZATION_TABS;
else
tabs_kind= WALK_EXECUTION_TABS;
if (table_count)
{
for (tab= first_breadth_first_tab(this, tabs_kind); tab;
tab= next_breadth_first_tab(this, tabs_kind, tab))
{
for (tab= first_breadth_first_optimization_tab(); tab;
tab= next_breadth_first_tab(this, WALK_OPTIMIZATION_TABS, tab))
tab->cleanup();
}
if (tabs_kind == WALK_OPTIMIZATION_TABS &&
first_breadth_first_tab(this, WALK_OPTIMIZATION_TABS) !=
first_breadth_first_tab(this, WALK_EXECUTION_TABS))
/* We've walked optimization tabs, do execution ones too. */
if (first_breadth_first_execution_tab() !=
first_breadth_first_optimization_tab())
{
JOIN_TAB *jt= first_breadth_first_tab(this, WALK_EXECUTION_TABS);
/* We've walked optimization tabs. do execution ones too */
if (jt)
jt->cleanup();
for (tab= first_breadth_first_execution_tab(); tab;
tab= next_breadth_first_tab(this, WALK_EXECUTION_TABS, tab))
tab->cleanup();
}
}
cleaned= true;
@ -23556,13 +23549,13 @@ int append_possible_keys(MEM_ROOT *alloc, String_list &list, TABLE *table,
void JOIN_TAB::update_explain_data(uint idx)
{
if (this == first_breadth_first_tab(join, WALK_OPTIMIZATION_TABS) + join->const_tables &&
if (this == join->first_breadth_first_optimization_tab() + join->const_tables &&
join->select_lex->select_number != INT_MAX &&
join->select_lex->select_number != UINT_MAX)
{
Explain_table_access *eta= new (join->thd->mem_root) Explain_table_access(join->thd->mem_root);
JOIN_TAB* const first_top_tab= first_breadth_first_tab(join, WALK_OPTIMIZATION_TABS);
save_explain_data(eta, join->const_table_map, join->select_distinct, first_top_tab);
save_explain_data(eta, join->const_table_map, join->select_distinct,
join->first_breadth_first_optimization_tab());
Explain_select *sel= join->thd->lex->explain->get_select(join->select_lex->select_number);
idx -= my_count_bits(join->eliminated_tables);
@ -24059,7 +24052,7 @@ int JOIN::save_explain_data_intern(Explain_query *output, bool need_tmp_table,
xpl_sel->exec_const_cond= exec_const_cond;
JOIN_TAB* const first_top_tab= first_breadth_first_tab(join, WALK_OPTIMIZATION_TABS);
JOIN_TAB* const first_top_tab= join->first_breadth_first_optimization_tab();
JOIN_TAB* prev_bush_root_tab= NULL;
Explain_basic_join *cur_parent= xpl_sel;

2
sql/sql_select.h
View File

@ -1531,6 +1531,8 @@ public:
int save_explain_data_intern(Explain_query *output, bool need_tmp_table,
bool need_order, bool distinct,
const char *message);
JOIN_TAB *first_breadth_first_optimization_tab() { return table_access_tabs; }
JOIN_TAB *first_breadth_first_execution_tab() { return join_tab; }
private:
/**
TRUE if the query contains an aggregate function but has no GROUP