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MDEV-33281 Make BNL() hint work for join_cache_levels from 0 to 3

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BNL() hint effectively increases join_cache_level up to 4 if it is
set to value less than 4.
This commit also makes the BKA() hint override not only
`join_cache_bka` optimizer switch but `join_cache_level` as well.
I.e., BKA() hint enables BKA and BKAH join buffers both flat and
incremental despite `join_cache_level` and `join_cache_bka` setting.
This commit is contained in:
Oleg Smirnov 2024-09-16 21:53:20 +07:00
parent e4af72bd5d
commit 1e2774d829
3 changed files with 110 additions and 3 deletions
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60
mysql-test/main/opt_hints.result
View File

@ -353,6 +353,32 @@ id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t13 ref a a 5 test.t12.a 1 100.00 Using index condition; Using where; Using join buffer (flat, BKAH join); Rowid-ordered scan
Warnings:
Note 1003 select /*+ QB_NAME(`QB1`) BKA(`t13`@`QB1`) */ `test`.`t12`.`a` AS `a`,`test`.`t12`.`b` AS `b`,`test`.`t13`.`a` AS `a`,`test`.`t13`.`b` AS `b`,`test`.`t13`.`c` AS `c`,`test`.`t13`.`filler` AS `filler` from `test`.`t12` join `test`.`t13` where `test`.`t13`.`a` = `test`.`t12`.`a` and `test`.`t13`.`b` + 1 <= `test`.`t13`.`b` + 1
# Hint overrides both join_cache_level and optimizer switch
set join_cache_level = 0;
EXPLAIN EXTENDED SELECT /*+ BKA(t12, t13) */ * FROM t12, t13
WHERE t12.a=t13.a AND (t13.b+1 <= t13.b+1);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t12 ALL NULL NULL NULL NULL 10 100.00 Using where
1 SIMPLE t13 ref a a 5 test.t12.a 1 100.00 Using index condition; Using where; Using join buffer (flat, BKAH join); Rowid-ordered scan
Warnings:
Note 1003 select /*+ BKA(`t12`@`select#1`) BKA(`t13`@`select#1`) */ `test`.`t12`.`a` AS `a`,`test`.`t12`.`b` AS `b`,`test`.`t13`.`a` AS `a`,`test`.`t13`.`b` AS `b`,`test`.`t13`.`c` AS `c`,`test`.`t13`.`filler` AS `filler` from `test`.`t12` join `test`.`t13` where `test`.`t13`.`a` = `test`.`t12`.`a` and `test`.`t13`.`b` + 1 <= `test`.`t13`.`b` + 1
set join_cache_level = 2;
EXPLAIN EXTENDED SELECT /*+ BKA(t12, t13) */ * FROM t12, t13
WHERE t12.a=t13.a AND (t13.b+1 <= t13.b+1);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t12 ALL NULL NULL NULL NULL 10 100.00 Using where
1 SIMPLE t13 ref a a 5 test.t12.a 1 100.00 Using index condition; Using where; Using join buffer (flat, BKAH join); Rowid-ordered scan
Warnings:
Note 1003 select /*+ BKA(`t12`@`select#1`) BKA(`t13`@`select#1`) */ `test`.`t12`.`a` AS `a`,`test`.`t12`.`b` AS `b`,`test`.`t13`.`a` AS `a`,`test`.`t13`.`b` AS `b`,`test`.`t13`.`c` AS `c`,`test`.`t13`.`filler` AS `filler` from `test`.`t12` join `test`.`t13` where `test`.`t13`.`a` = `test`.`t12`.`a` and `test`.`t13`.`b` + 1 <= `test`.`t13`.`b` + 1
set join_cache_level = 4;
EXPLAIN EXTENDED SELECT /*+ BKA(t12, t13) */ * FROM t12, t13
WHERE t12.a=t13.a AND (t13.b+1 <= t13.b+1);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t12 ALL NULL NULL NULL NULL 10 100.00 Using where
1 SIMPLE t13 ref a a 5 test.t12.a 1 100.00 Using index condition; Using where; Using join buffer (flat, BKAH join); Rowid-ordered scan
Warnings:
Note 1003 select /*+ BKA(`t12`@`select#1`) BKA(`t13`@`select#1`) */ `test`.`t12`.`a` AS `a`,`test`.`t12`.`b` AS `b`,`test`.`t13`.`a` AS `a`,`test`.`t13`.`b` AS `b`,`test`.`t13`.`c` AS `c`,`test`.`t13`.`filler` AS `filler` from `test`.`t12` join `test`.`t13` where `test`.`t13`.`a` = `test`.`t12`.`a` and `test`.`t13`.`b` + 1 <= `test`.`t13`.`b` + 1
set join_cache_level = 8;
# Enable BKA
set optimizer_switch='join_cache_bka=on';
EXPLAIN EXTENDED SELECT /*+ NO_BKA(t13) */ * FROM t12, t13
@ -1175,6 +1201,40 @@ LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
a4 b5
9 0
9 NULL
# BNL() hint overrides join_cache_levels from 0 to 3 increasing it to 4
set join_cache_level = 1;
EXPLAIN
SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
1 SIMPLE t3 index PRIMARY PRIMARY 4 NULL 1 Using where; Using index
1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t3.a3 1 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t5 hash_ALL PRIMARY #hash#PRIMARY 4 test.t2.a2 1 Using where; Using join buffer (incremental, BNLH join)
set join_cache_level = 2;
EXPLAIN
SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
1 SIMPLE t3 index PRIMARY PRIMARY 4 NULL 1 Using where; Using index
1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t3.a3 1 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t5 hash_ALL PRIMARY #hash#PRIMARY 4 test.t2.a2 1 Using where; Using join buffer (incremental, BNLH join)
set join_cache_level = 3;
EXPLAIN
SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
1 SIMPLE t2 ALL PRIMARY NULL NULL NULL 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.a2 1 Using index
1 SIMPLE t4 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (flat, BNL join)
1 SIMPLE t5 hash_ALL PRIMARY #hash#PRIMARY 4 test.t2.a2 1 Using where; Using join buffer (incremental, BNLH join)
# Enable all join buffering capabilities:
SET SESSION join_cache_level = 8;
EXPLAIN

34
mysql-test/main/opt_hints.test
View File

@ -197,6 +197,21 @@ EXPLAIN EXTENDED SELECT /*+ BKA(t12) */ * FROM t12, t13
EXPLAIN EXTENDED SELECT /*+ QB_NAME(QB1) BKA(t13@QB1) */ * FROM t12, t13
WHERE t12.a=t13.a AND (t13.b+1 <= t13.b+1);
--echo # Hint overrides both join_cache_level and optimizer switch
set join_cache_level = 0;
EXPLAIN EXTENDED SELECT /*+ BKA(t12, t13) */ * FROM t12, t13
WHERE t12.a=t13.a AND (t13.b+1 <= t13.b+1);
set join_cache_level = 2;
EXPLAIN EXTENDED SELECT /*+ BKA(t12, t13) */ * FROM t12, t13
WHERE t12.a=t13.a AND (t13.b+1 <= t13.b+1);
set join_cache_level = 4;
EXPLAIN EXTENDED SELECT /*+ BKA(t12, t13) */ * FROM t12, t13
WHERE t12.a=t13.a AND (t13.b+1 <= t13.b+1);
set join_cache_level = 8;
--echo # Enable BKA
set optimizer_switch='join_cache_bka=on';
@ -603,6 +618,25 @@ SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
--echo # BNL() hint overrides join_cache_levels from 0 to 3 increasing it to 4
set join_cache_level = 1;
EXPLAIN
SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
set join_cache_level = 2;
EXPLAIN
SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
set join_cache_level = 3;
EXPLAIN
SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
--echo # Enable all join buffering capabilities:
SET SESSION join_cache_level = 8;
EXPLAIN

19
sql/sql_select.cc
View File

@ -15715,12 +15715,15 @@ uint check_join_cache_usage(JOIN_TAB *tab,
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);
join->return_tab= 0;
if (tab->no_forced_join_cache || (no_bnl_cache && no_bka_cache))
goto no_join_cache;
if (cache_level == 0 && hint_table_state_or_fallback(join->thd,
if (cache_level < 4 && hint_table_state_or_fallback(join->thd,
tab->tab_list->table,
BNL_HINT_ENUM, false))
{
@ -15728,11 +15731,19 @@ uint check_join_cache_usage(JOIN_TAB *tab,
}
/*
Don't use join cache if @@join_cache_level==0 or this table is the first
Don't use join cache if @@join_cache_level==0 and hint BKA()
is not specified or this table is the first
one join suborder (either at top level or inside a bush)
*/
if (cache_level == 0 || !prev_tab)
if ((cache_level == 0 && !hint_forces_bka) || !prev_tab)
{
/*
We could have cache_level==0 but join cache was forced for some previous
table (PT) with a hint. Proceed to cancel join cache for PT if it is not
allowed to use join cache for PT without using it for this table.
*/
goto no_join_cache;
}
if (force_unlinked_cache && (cache_level%2 == 0))
cache_level--;
@ -15871,6 +15882,8 @@ uint check_join_cache_usage(JOIN_TAB *tab,
case JT_CONST:
case JT_REF:
case JT_EQ_REF:
if (hint_forces_bka)
cache_level= 8; // Increase to BKAH incremental
if (cache_level <=2 || (no_hashed_cache && no_bka_cache))
goto no_join_cache;
if (tab->ref.is_access_triggered())