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MDEV-33281 Make BNL() hint enable hashed join buffers

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Since BNL() hint does not specify which whether hashed or non-hashed
join cache should be employed, allow usage of hashed ones
where possible
This commit is contained in:
Oleg Smirnov
2024-11-27 14:34:24 +07:00
parent 67319f3e8d
commit af14196b8a
7 changed files with 69 additions and 67 deletions
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60
sql/sql_select.cc
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@@ -6662,7 +6662,7 @@ add_key_field(JOIN *join,
{
uint optimize= 0;
if (eq_func &&
((join->is_allowed_hash_join_access() &&
((join->is_allowed_hash_join_access(field->table) &&
field->hash_join_is_possible() &&
!(field->table->pos_in_table_list->is_materialized_derived() &&
field->table->is_created())) ||
@@ -9428,8 +9428,7 @@ best_access_path(JOIN *join,
(2) s is inner table of outer join -> join cache is allowed for outer joins
*/
if (idx > join->const_tables && best.key == 0 &&
(join->allowed_join_cache_types & JOIN_CACHE_HASHED_BIT) &&
join->max_allowed_join_cache_level > 2 &&
join->is_allowed_hash_join_access(table) &&
!bitmap_is_clear_all(eq_join_set) && !disable_jbuf &&
(!s->emb_sj_nest ||
join->allowed_semijoin_with_cache) && // (1)
@@ -11468,7 +11467,6 @@ get_costs_for_tables(JOIN *join, table_map remaining_tables, uint idx,
JOIN_TAB *s;
table_map found_tables= 0;
bool found_eq_ref= 0;
bool disable_jbuf= join->thd->variables.join_cache_level == 0;
DBUG_ENTER("get_plans_for_tables");
s= *pos;
@@ -11485,6 +11483,11 @@ get_costs_for_tables(JOIN *join, table_map remaining_tables, uint idx,
sort_end->join_tab= pos;
sort_end->position= sort_position;
bool hint_forces_jbuf=
hint_table_state(join->thd, s->table, BNL_HINT_ENUM, false);
bool disable_jbuf=
(join->thd->variables.join_cache_level == 0) && !hint_forces_jbuf;
Json_writer_object wrapper(thd);
/* Find the best access method from 's' to the current partial plan */
@@ -14471,11 +14474,17 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
add_cond_and_fix(thd, &tmp, tab->select_cond);
}
uint max_jcl= join->max_allowed_join_cache_level;
bool is_hash_allowed= join->allowed_join_cache_types &
JOIN_CACHE_HASHED_BIT;
bool is_bnlh_enabled= ((max_jcl == 3 || max_jcl == 4) &&
is_hash_allowed) ||
hint_table_state(thd, tab->table, BNL_HINT_ENUM, false);
bool is_bkah_enabled= (max_jcl > 4 && is_hash_allowed) ||
hint_table_state(thd, tab->table, BKA_HINT_ENUM, false);
is_hj= (tab->type == JT_REF || tab->type == JT_EQ_REF) &&
(join->allowed_join_cache_types & JOIN_CACHE_HASHED_BIT) &&
((join->max_allowed_join_cache_level+1)/2 == 2 ||
((join->max_allowed_join_cache_level+1)/2 > 2 &&
is_hash_join_key_no(tab->ref.key))) &&
(is_bnlh_enabled ||
(is_bkah_enabled && is_hash_join_key_no(tab->ref.key))) &&
(!tab->emb_sj_nest ||
join->allowed_semijoin_with_cache) &&
(!(tab->table->map & join->outer_join) ||
@@ -15631,17 +15640,14 @@ end_sj_materialize(JOIN *join, JOIN_TAB *join_tab, bool end_of_records)
OPTIMIZER_HINTS
The following hints may influence the choice of join buffering:
BNL(t1,t2,..): enables BNL and BNLH buffers for the specified tables
when join_cache_level=0. Effectively it increases
when join_cache_level < 4. It effectively increases
join_cache_level to 4 for given tables.
NO_BNL(t1,t2,..): disables BNL/BNLH join buffers, which could have been
chosen for the specified tables otherwise. Does not
prevent employing of BKA/BKAH buffers
BKA(t1,t2,..): enables BKA and BKAH buffers for the specified tables
when optimizer switch join_cache_bka=off. Does not
increase join_cache_level, i.e., when join_cache_level=4
and the hint is specified, BKA join buffers will still
not be employed. The hint effectively overrides only
optimizer switch join_cache_bka setting.
when join_cache_level < 5 and/or
optimizer switch join_cache_bka=off.
NO_BKA(t1,t2,..): disables BKA/BKAH join buffers, which could have been
chosen for the specified tables otherwise. However,
does not prevent employing of BNL/BNLH buffers.
@@ -15710,22 +15716,19 @@ uint check_join_cache_usage(JOIN_TAB *tab,
!(join->allowed_join_cache_types & JOIN_CACHE_INCREMENTAL_BIT);
bool no_hashed_cache=
!(join->allowed_join_cache_types & JOIN_CACHE_HASHED_BIT);
bool no_bnl_cache= !hint_table_state_or_fallback(join->thd,
tab->tab_list->table, BNL_HINT_ENUM, true);
bool no_bka_cache= !hint_table_state_or_fallback(join->thd,
tab->tab_list->table, BKA_HINT_ENUM,
join->allowed_join_cache_types & JOIN_CACHE_BKA_BIT);
bool hint_forces_bka= hint_table_state_or_fallback(join->thd,
tab->tab_list->table,
BKA_HINT_ENUM, false);
bool no_bnl_cache= !hint_table_state(join->thd, tab->tab_list->table,
BNL_HINT_ENUM, true);
bool no_bka_cache= !hint_table_state(join->thd, tab->tab_list->table,
BKA_HINT_ENUM, join->allowed_join_cache_types & JOIN_CACHE_BKA_BIT);
bool hint_forces_bka= hint_table_state(join->thd, tab->tab_list->table,
BKA_HINT_ENUM, false);
join->return_tab= 0;
if (tab->no_forced_join_cache || (no_bnl_cache && no_bka_cache))
goto no_join_cache;
if (cache_level < 4 && hint_table_state_or_fallback(join->thd,
tab->tab_list->table,
BNL_HINT_ENUM, false))
if (cache_level < 4 && hint_table_state(join->thd, tab->tab_list->table,
BNL_HINT_ENUM, false))
{
cache_level= 4; // BNL() hint present, raise join_cache_level to BNLH
}
@@ -32445,6 +32448,13 @@ void JOIN::set_allowed_join_cache_types()
max_allowed_join_cache_level= thd->variables.join_cache_level;
}
bool JOIN::is_allowed_hash_join_access(const TABLE *table)
{
return allowed_join_cache_types & JOIN_CACHE_HASHED_BIT &&
(max_allowed_join_cache_level > JOIN_CACHE_HASHED_BIT ||
hint_table_state(thd, table, BNL_HINT_ENUM, false) ||
hint_table_state(thd, table, BKA_HINT_ENUM, false));
}
/**
Save a query execution plan so that the caller can revert to it if needed,