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Commit 4329ec5d authored by Sergei Petrunia's avatar Sergei Petrunia
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MDEV-30812: Improve output cardinality estimates for hash join 

Introduce @@optimizer_switch flag: hash_join_cardinality

When it is on, use EITS statistics to produce tighter bounds for
hash join output cardinality.

Amended by Monty.

Reviewed by: Monty <monty@mariadb.org>
parent 2eb7bf1e
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Showing with 363 additions and 53 deletions
mysql-test/main/join_cache_cardinality.result 0 → 100644
View file @ 4329ec5d
create table t1 (a int, b int, c int);
insert into t1 select seq,seq/2, seq/4 from seq_1_to_100;
create table t2 (a int, b int, c int);
insert into t2 select seq, seq/2, seq/4 from seq_1_to_200;
analyze table t1,t2 persistent for all;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
test.t2 analyze status Engine-independent statistics collected
test.t2 analyze status OK
set optimizer_trace=1;
set join_cache_level=6;
set optimizer_switch='hash_join_cardinality=on';
explain select *
from t1, t2
where t1.a=t2.a and t1.a=t2.b and t1.c=t2.c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE t2 hash_ALL NULL #hash#$hj 15 test.t1.a,test.t1.a,test.t1.c 200 Using where; Using join buffer (flat, BNLH join)
set @json= (select trace from information_schema.optimizer_trace);
select json_detailed(json_extract(@json, '$**.hash_join_cardinality')) as JS;
JS
[
{
"hash_join_columns":
[
{
"field": "a",
"avg_frequency": 1
},
{
"field": "b",
"avg_frequency": 2
},
{
"field": "c",
"avg_frequency": 3.9216
}
],
"rows": 1
}
]
select json_detailed(json_extract(@json, '$**.rest_of_plan[*].rows_for_plan'))
as ROWS_FOR_PLAN;
ROWS_FOR_PLAN
[100]
explain select *
from t1, t2 where t1.c=t2.c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE t2 hash_ALL NULL #hash#$hj 5 test.t1.c 200 Using where; Using join buffer (flat, BNLH join)
set @json= (select trace from information_schema.optimizer_trace);
select json_detailed(json_extract(@json, '$**.hash_join_cardinality')) as JS;
JS
[
{
"hash_join_columns":
[
{
"field": "c",
"avg_frequency": 3.9216
}
],
"rows": 3.9216
}
]
select json_detailed(json_extract(@json, '$**.rest_of_plan[*].rows_for_plan'))
as ROWS_FOR_PLAN;
ROWS_FOR_PLAN
[392.16]
explain select *
from t1 straight_join t2 where t1.c=t2.c and t2.a<30;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 Using where
1 SIMPLE t2 hash_ALL NULL #hash#$hj 5 test.t1.c 200 Using where; Using join buffer (flat, BNLH join)
set @json= (select trace from information_schema.optimizer_trace);
# Note that rows is the same:
select json_detailed(json_extract(@json, '$**.hash_join_cardinality')) as JS;
JS
[
{
"hash_join_columns":
[
{
"field": "c",
"avg_frequency": 3.9216
}
],
"rows": 3.9216
}
]
# Despite available selectivity:
select json_detailed(json_extract(@json, '$**.selectivity_for_columns')) as JS;
JS
[
[
{
"column_name": "a",
"ranges":
["NULL < a < 30"],
"selectivity_from_histogram": 0.1484375
}
]
]
drop table t1,t2;
mysql-test/main/join_cache_cardinality.test 0 → 100644
View file @ 4329ec5d
--source include/have_sequence.inc
# Embedded doesn't have optimizer trace:
--source include/not_embedded.inc
create table t1 (a int, b int, c int);
insert into t1 select seq,seq/2, seq/4 from seq_1_to_100;
create table t2 (a int, b int, c int);
insert into t2 select seq, seq/2, seq/4 from seq_1_to_200;
analyze table t1,t2 persistent for all;
set optimizer_trace=1;
set join_cache_level=6;
set optimizer_switch='hash_join_cardinality=on';
explain select *
from t1, t2
where t1.a=t2.a and t1.a=t2.b and t1.c=t2.c;
set @json= (select trace from information_schema.optimizer_trace);
select json_detailed(json_extract(@json, '$**.hash_join_cardinality')) as JS;
select json_detailed(json_extract(@json, '$**.rest_of_plan[*].rows_for_plan'))
as ROWS_FOR_PLAN;
explain select *
from t1, t2 where t1.c=t2.c;
set @json= (select trace from information_schema.optimizer_trace);
select json_detailed(json_extract(@json, '$**.hash_join_cardinality')) as JS;
select json_detailed(json_extract(@json, '$**.rest_of_plan[*].rows_for_plan'))
as ROWS_FOR_PLAN;
explain select *
from t1 straight_join t2 where t1.c=t2.c and t2.a<30;
set @json= (select trace from information_schema.optimizer_trace);
--echo # Note that rows is the same:
select json_detailed(json_extract(@json, '$**.hash_join_cardinality')) as JS;
--echo # Despite available selectivity:
select json_detailed(json_extract(@json, '$**.selectivity_for_columns')) as JS;
drop table t1,t2;
mysql-test/main/mysqld--help.result
View file @ 4329ec5d
......@@ -734,7 +734,8 @@ The following specify which files/extra groups are read (specified before remain
extended_keys, exists_to_in, orderby_uses_equalities,
condition_pushdown_for_derived, split_materialized,
condition_pushdown_for_subquery, rowid_filter,
condition_pushdown_from_having, not_null_range_scan
condition_pushdown_from_having, not_null_range_scan,
hash_join_cardinality
--optimizer-trace=name
Controls tracing of the Optimizer:
optimizer_trace=option=val[,option=val...], where option
......
mysql-test/main/mysqltest_tracking_info.result
View file @ 4329ec5d
......@@ -38,7 +38,7 @@ SET @@session.session_track_system_variables='optimizer_switch';
set optimizer_switch='index_merge=off,index_merge_union=off,index_merge_sort_union=off,index_merge_intersection=off,index_merge_sort_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=on,mrr_cost_based=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=on,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off';
-- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
-- optimizer_switch
-- index_merge=off,index_merge_union=off,index_merge_sort_union=off,index_merge_intersection=off,index_merge_sort_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=on,mrr_cost_based=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=on,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off
-- index_merge=off,index_merge_union=off,index_merge_sort_union=off,index_merge_intersection=off,index_merge_sort_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=on,mrr_cost_based=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=on,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off,hash_join_cardinality=off
Warnings:
Warning 1681 'engine_condition_pushdown=on' is deprecated and will be removed in a future release
......
mysql-test/suite/sys_vars/r/optimizer_switch_basic.result
View file @ 4329ec5d
set @@global.optimizer_switch=@@optimizer_switch;
select @@global.optimizer_switch;
@@global.optimizer_switch
index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off
index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off,hash_join_cardinality=off
select @@session.optimizer_switch;
@@session.optimizer_switch
index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off
index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off,hash_join_cardinality=off
show global variables like 'optimizer_switch';
Variable_name Value
optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off
optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off,hash_join_cardinality=off
show session variables like 'optimizer_switch';
Variable_name Value
optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off
optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off,hash_join_cardinality=off
select * from information_schema.global_variables where variable_name='optimizer_switch';
VARIABLE_NAME VARIABLE_VALUE
OPTIMIZER_SWITCH index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off
OPTIMIZER_SWITCH index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off,hash_join_cardinality=off
select * from information_schema.session_variables where variable_name='optimizer_switch';
VARIABLE_NAME VARIABLE_VALUE
OPTIMIZER_SWITCH index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off
OPTIMIZER_SWITCH index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off,hash_join_cardinality=off
set global optimizer_switch=4101;
set session optimizer_switch=2058;
select @@global.optimizer_switch;
@@global.optimizer_switch
index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off
index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off,hash_join_cardinality=off
select @@session.optimizer_switch;
@@session.optimizer_switch
index_merge=off,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off
index_merge=off,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off,hash_join_cardinality=off
set global optimizer_switch="index_merge_sort_union=on";
set session optimizer_switch="index_merge=off";
select @@global.optimizer_switch;
@@global.optimizer_switch
index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off
index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off,hash_join_cardinality=off
select @@session.optimizer_switch;
@@session.optimizer_switch
index_merge=off,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off
index_merge=off,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off,hash_join_cardinality=off
show global variables like 'optimizer_switch';
Variable_name Value
optimizer_switch index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off
optimizer_switch index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off,hash_join_cardinality=off
show session variables like 'optimizer_switch';
Variable_name Value
optimizer_switch index_merge=off,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off
optimizer_switch index_merge=off,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off,hash_join_cardinality=off
select * from information_schema.global_variables where variable_name='optimizer_switch';
VARIABLE_NAME VARIABLE_VALUE
OPTIMIZER_SWITCH index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off
OPTIMIZER_SWITCH index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off,hash_join_cardinality=off
select * from information_schema.session_variables where variable_name='optimizer_switch';
VARIABLE_NAME VARIABLE_VALUE
OPTIMIZER_SWITCH index_merge=off,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off
OPTIMIZER_SWITCH index_merge=off,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off,hash_join_cardinality=off
set session optimizer_switch="default";
select @@session.optimizer_switch;
@@session.optimizer_switch
index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off
index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=off,condition_pushdown_for_subquery=off,rowid_filter=off,condition_pushdown_from_having=off,not_null_range_scan=off,hash_join_cardinality=off
set optimizer_switch = replace(@@optimizer_switch, '=off', '=on');
Warnings:
Warning 1681 'engine_condition_pushdown=on' is deprecated and will be removed in a future release
select @@optimizer_switch;
@@optimizer_switch
index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=on,mrr_cost_based=on,mrr_sort_keys=on,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=on
index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=on,mrr_cost_based=on,mrr_sort_keys=on,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=on,hash_join_cardinality=on
set global optimizer_switch=1.1;
ERROR 42000: Incorrect argument type to variable 'optimizer_switch'
set global optimizer_switch=1e1;
......
mysql-test/suite/sys_vars/r/sysvars_server_embedded.result
View file @ 4329ec5d
......@@ -2299,7 +2299,7 @@ VARIABLE_COMMENT Fine-tune the optimizer behavior
NUMERIC_MIN_VALUE NULL
NUMERIC_MAX_VALUE NULL
NUMERIC_BLOCK_SIZE NULL
ENUM_VALUE_LIST index_merge,index_merge_union,index_merge_sort_union,index_merge_intersection,index_merge_sort_intersection,engine_condition_pushdown,index_condition_pushdown,derived_merge,derived_with_keys,firstmatch,loosescan,materialization,in_to_exists,semijoin,partial_match_rowid_merge,partial_match_table_scan,subquery_cache,mrr,mrr_cost_based,mrr_sort_keys,outer_join_with_cache,semijoin_with_cache,join_cache_incremental,join_cache_hashed,join_cache_bka,optimize_join_buffer_size,table_elimination,extended_keys,exists_to_in,orderby_uses_equalities,condition_pushdown_for_derived,split_materialized,condition_pushdown_for_subquery,rowid_filter,condition_pushdown_from_having,not_null_range_scan,default
ENUM_VALUE_LIST index_merge,index_merge_union,index_merge_sort_union,index_merge_intersection,index_merge_sort_intersection,engine_condition_pushdown,index_condition_pushdown,derived_merge,derived_with_keys,firstmatch,loosescan,materialization,in_to_exists,semijoin,partial_match_rowid_merge,partial_match_table_scan,subquery_cache,mrr,mrr_cost_based,mrr_sort_keys,outer_join_with_cache,semijoin_with_cache,join_cache_incremental,join_cache_hashed,join_cache_bka,optimize_join_buffer_size,table_elimination,extended_keys,exists_to_in,orderby_uses_equalities,condition_pushdown_for_derived,split_materialized,condition_pushdown_for_subquery,rowid_filter,condition_pushdown_from_having,not_null_range_scan,hash_join_cardinality,default
READ_ONLY NO
COMMAND_LINE_ARGUMENT REQUIRED
VARIABLE_NAME OPTIMIZER_TRACE
......
mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result
View file @ 4329ec5d
......@@ -2459,7 +2459,7 @@ VARIABLE_COMMENT Fine-tune the optimizer behavior
NUMERIC_MIN_VALUE NULL
NUMERIC_MAX_VALUE NULL
NUMERIC_BLOCK_SIZE NULL
ENUM_VALUE_LIST index_merge,index_merge_union,index_merge_sort_union,index_merge_intersection,index_merge_sort_intersection,engine_condition_pushdown,index_condition_pushdown,derived_merge,derived_with_keys,firstmatch,loosescan,materialization,in_to_exists,semijoin,partial_match_rowid_merge,partial_match_table_scan,subquery_cache,mrr,mrr_cost_based,mrr_sort_keys,outer_join_with_cache,semijoin_with_cache,join_cache_incremental,join_cache_hashed,join_cache_bka,optimize_join_buffer_size,table_elimination,extended_keys,exists_to_in,orderby_uses_equalities,condition_pushdown_for_derived,split_materialized,condition_pushdown_for_subquery,rowid_filter,condition_pushdown_from_having,not_null_range_scan,default
ENUM_VALUE_LIST index_merge,index_merge_union,index_merge_sort_union,index_merge_intersection,index_merge_sort_intersection,engine_condition_pushdown,index_condition_pushdown,derived_merge,derived_with_keys,firstmatch,loosescan,materialization,in_to_exists,semijoin,partial_match_rowid_merge,partial_match_table_scan,subquery_cache,mrr,mrr_cost_based,mrr_sort_keys,outer_join_with_cache,semijoin_with_cache,join_cache_incremental,join_cache_hashed,join_cache_bka,optimize_join_buffer_size,table_elimination,extended_keys,exists_to_in,orderby_uses_equalities,condition_pushdown_for_derived,split_materialized,condition_pushdown_for_subquery,rowid_filter,condition_pushdown_from_having,not_null_range_scan,hash_join_cardinality,default
READ_ONLY NO
COMMAND_LINE_ARGUMENT REQUIRED
VARIABLE_NAME OPTIMIZER_TRACE
......
sql/sql_priv.h
View file @ 4329ec5d
......@@ -234,6 +234,7 @@
#define OPTIMIZER_SWITCH_USE_ROWID_FILTER (1ULL << 33)
#define OPTIMIZER_SWITCH_COND_PUSHDOWN_FROM_HAVING (1ULL << 34)
#define OPTIMIZER_SWITCH_NOT_NULL_RANGE_SCAN (1ULL << 35)
#define OPTIMIZER_SWITCH_HASH_JOIN_CARDINALITY (1ULL << 36)
#define OPTIMIZER_SWITCH_DEFAULT (OPTIMIZER_SWITCH_INDEX_MERGE | \
OPTIMIZER_SWITCH_INDEX_MERGE_UNION | \
......
sql/sql_select.cc
View file @ 4329ec5d
......@@ -7597,20 +7597,28 @@ void set_position(JOIN *join,uint idx,JOIN_TAB *table,KEYUSE *key)
Estimate how many records we will get if we read just this table and apply
a part of WHERE that can be checked for it.
@param s Current JOIN_TAB
@param use_cond_selectivity Value of optimizer_use_condition_selectivity.
If > 1 then use table->cond_selecitivity.
@param force_estiamte Set to 1 if we should not call
use_found_constraint. To be deleted in 11.0
@return 0.0 No matching rows
@return >= 1.0 Number of expected matching rows
@detail
Estimate how many records we will get if we
- read the given table with its "independent" access method (either quick
select or full table/index scan),
- apply the part of WHERE that refers only to this table.
@seealso
@see also
table_cond_selectivity() produces selectivity of condition that is checked
after joining rows from this table to rows from preceding tables.
*/
inline
double matching_candidates_in_table(JOIN_TAB *s, bool with_found_constraint,
uint use_cond_selectivity)
static double apply_selectivity_for_table(JOIN_TAB *s,
uint use_cond_selectivity,
bool *force_estimate)
{
ha_rows records;
double dbl_records;
......@@ -7621,12 +7629,32 @@ double matching_candidates_in_table(JOIN_TAB *s, bool with_found_constraint,
double sel= table->cond_selectivity;
double table_records= rows2double(s->records);
dbl_records= table_records * sel;
*force_estimate= 1; // Don't call use_found_constraint()
return dbl_records;
}
records = s->found_records;
/*
If applicable, get a more accurate estimate.
*/
DBUG_ASSERT(s->table->opt_range_condition_rows <= s->found_records);
if (s->table->opt_range_condition_rows != s->found_records)
{
*force_estimate= 1; // Don't call use_found_constraint()
records= s->table->opt_range_condition_rows;
}
dbl_records= (double)records;
return dbl_records;
}
/*
Take into account that the table's WHERE clause has conditions on earlier
tables that can reduce the number of accepted rows.
@param records Number of original rows (after selectivity)
If there is a filtering condition on the table (i.e. ref analyzer found
at least one "table.keyXpartY= exprZ", where exprZ refers only to tables
preceding this table in the join order we're now considering), then
......@@ -7634,19 +7662,12 @@ double matching_candidates_in_table(JOIN_TAB *s, bool with_found_constraint,
This heuristic is supposed to force tables used in exprZ to be before
this table in join order.
*/
if (with_found_constraint)
records-= records/4;
/*
If applicable, get a more accurate estimate. Don't use the two
heuristics at once.
*/
if (s->table->opt_range_condition_rows != s->found_records)
records= s->table->opt_range_condition_rows;
*/
dbl_records= (double)records;
return dbl_records;
inline double use_found_constraint(double records)
{
records-= records/4;
return records;
}
......@@ -7705,6 +7726,92 @@ double adjust_quick_cost(double quick_cost, ha_rows records)
}
/*
@brief
Compute the fanout of hash join operation using EITS data
*/
double hash_join_fanout(JOIN *join, JOIN_TAB *s, table_map remaining_tables,
double rnd_records, KEYUSE *hj_start_key,
bool *stats_found)
{
THD *thd= join->thd;
/*
Before doing the hash join, we will scan the table and apply the local part
of the WHERE condition. This will produce rnd_records.
The EITS statistics describes the entire table. Calling
table->field[N]->get_avg_frequency()
produces average #rows in the table with some value.
What happens if we filter out rows so that rnd_records rows are left?
Something between the two outcomes:
A. filtering removes a fraction of rows for each value:
avg_frequency=avg_frequency * condition_selectivity
B. filtering removes entire groups of rows with the same value, but
the remaining groups remain of the same size.
We make pessimistic assumption and assume B.
We also handle an edge case: if rnd_records is less than avg_frequency,
assume we'll get rnd_records rows with the same value, and return
rnd_records as the fanout estimate.
*/
double min_freq= rnd_records;
Json_writer_object trace_obj(thd, "hash_join_cardinality");
/*
There can be multiple KEYUSE referring to same or different columns
KEYUSE(tbl.col1 = ...)
KEYUSE(tbl.col1 = ...)
KEYUSE(tbl.col2 = ...)
Hash join code can use multiple columns: (col1, col2) for joining.
We need n_distinct({col1, col2}).
EITS only has statistics on individual columns: n_distinct(col1),
n_distinct(col2).
Our current solution is to be very conservative and use selectivity
of one column with the lowest avg_frequency.
In the future, we should an approach that cautiosly takes into account
multiple KEYUSEs either multiply by number of equalities or by sqrt
of the second most selective equality.
*/
Json_writer_array trace_arr(thd, "hash_join_columns");
for (KEYUSE *keyuse= hj_start_key;
keyuse->table == s->table && is_hash_join_key_no(keyuse->key);
keyuse++)
{
if (!(remaining_tables & keyuse->used_tables) &&
(!keyuse->validity_ref || *keyuse->validity_ref) &&
s->access_from_tables_is_allowed(keyuse->used_tables,
join->sjm_lookup_tables))
{
Field *field= s->table->field[keyuse->keypart];
if (is_eits_usable(field))
{
double freq= field->read_stats->get_avg_frequency();
Json_writer_object trace_field(thd);
trace_field.add("field",field->field_name.str).
add("avg_frequency", freq);
if (freq < min_freq)
min_freq= freq;
*stats_found= 1;
}
}
}
trace_arr.end();
trace_obj.add("rows", min_freq);
return min_freq;
}
/**
Find the best access path for an extension of a partial execution
plan and add this path to the plan.
......@@ -8399,11 +8506,44 @@ best_access_path(JOIN *join,
(!(s->table->map & join->outer_join) ||
join->allowed_outer_join_with_cache)) // (2)
{
double fanout;
Json_writer_object trace_access_hash(thd);
double join_sel= 0.1;
trace_access_hash.add("type", "hash");
trace_access_hash.add("index", "hj-key");
double join_sel;
bool stats_found= 0, force_estimate= 0;
/* Estimate the cost of the hash join access to the table */
double rnd_records= matching_candidates_in_table(s, found_constraint,
use_cond_selectivity);
double rnd_records= apply_selectivity_for_table(s, use_cond_selectivity,
&force_estimate);
DBUG_ASSERT(hj_start_key);
if (optimizer_flag(thd, OPTIMIZER_SWITCH_HASH_JOIN_CARDINALITY))
{
/*
Starting from this point, rnd_records should not be used anymore.
Use "fanout" for an estimate of # matching records.
*/
fanout= hash_join_fanout(join, s, remaining_tables, rnd_records,
hj_start_key, &stats_found);
join_sel= 1.0; // Don't do the "10% heuristic"
}
if (!stats_found)
{
/*
No OPTIMIZER_SWITCH_HASH_JOIN_CARDINALITY or no field statistics
found.
Take into account if there is non constant constraints used with
earlier tables in the where expression.
If yes, this will set fanout to rnd_records/4.
We estimate that there will be HASH_FANOUT (10%)
hash matches / row.
*/
if (found_constraint && !force_estimate)
rnd_records= use_found_constraint(rnd_records);
fanout= rnd_records;
join_sel= 0.1;
}
tmp= s->quick ? s->quick->read_time : s->scan_time();
double cmp_time= (s->records - rnd_records)/TIME_FOR_COMPARE;
......@@ -8415,19 +8555,36 @@ best_access_path(JOIN *join,
record_count /
(double) thd->variables.join_buff_size));
tmp= COST_MULT(tmp, refills);
best_time= COST_ADD(tmp,
COST_MULT((record_count*join_sel) / TIME_FOR_COMPARE,
rnd_records));
// Add cost of reading/writing the join buffer
if (optimizer_flag(thd, OPTIMIZER_SWITCH_HASH_JOIN_CARDINALITY))
{
/* Set it to be 1/10th of TIME_FOR_COMPARE */
double row_copy_cost= 1.0 / (10*TIME_FOR_COMPARE);
double join_buffer_operations=
COST_ADD(
COST_MULT(record_count, row_copy_cost),
COST_MULT(record_count, fanout * (idx - join->const_tables))
);
double jbuf_use_cost= row_copy_cost * join_buffer_operations;
trace_access_hash.add("jbuf_use_cost", jbuf_use_cost);
tmp= COST_ADD(tmp, jbuf_use_cost);
}
double where_cost= COST_MULT((fanout*join_sel) / TIME_FOR_COMPARE,
record_count);
trace_access_hash.add("extra_cond_check_cost", where_cost);
best_time= COST_ADD(tmp, where_cost);
best= tmp;
records= rnd_records;
records= fanout;
best_key= hj_start_key;
best_ref_depends_map= 0;
best_uses_jbuf= TRUE;
best_filter= 0;
best_type= JT_HASH;
trace_access_hash.add("type", "hash");
trace_access_hash.add("index", "hj-key");
trace_access_hash.add("cost", rnd_records);
trace_access_hash.add("records", records);
trace_access_hash.add("cost", best);
trace_access_hash.add("chosen", true);
}
......@@ -8479,9 +8636,13 @@ best_access_path(JOIN *join,
!(s->table->force_index && best_key && !s->quick) && // (4)
!(best_key && s->table->pos_in_table_list->jtbm_subselect)) // (5)
{ // Check full join
double rnd_records= matching_candidates_in_table(s, found_constraint,
use_cond_selectivity);
bool force_estimate= 0;
double rnd_records= apply_selectivity_for_table(s,
use_cond_selectivity,
&force_estimate);
rnd_records= ((found_constraint && !force_estimate) ?
use_found_constraint(rnd_records) :
rnd_records);
/*
Range optimizer never proposes a RANGE if it isn't better
than FULL: so if RANGE is present, it's always preferred to FULL.
......@@ -9698,7 +9859,7 @@ double table_multi_eq_cond_selectivity(JOIN *join, uint idx, JOIN_TAB *s,
with previous tables.
For quick selects and full table scans, selectivity of COND(this_table)
is accounted for in matching_candidates_in_table(). Here, we only count
is accounted for in apply_selectivity_for_table(). Here, we only count
selectivity of COND(this_table, previous_tables).
For other access methods, we need to calculate selectivity of the whole
......@@ -9900,7 +10061,7 @@ double table_cond_selectivity(JOIN *join, uint idx, JOIN_TAB *s,
/*
The table is accessed with full table scan, or quick select.
Selectivity of COND(table) is already accounted for in
matching_candidates_in_table().
apply_selectivity_for_table().
*/
sel= 1;
}
......
sql/sys_vars.cc
View file @ 4329ec5d
......@@ -2756,6 +2756,7 @@ export const char *optimizer_switch_names[]=
"rowid_filter",
"condition_pushdown_from_having",
"not_null_range_scan",
"hash_join_cardinality",
"default",
NullS
};
......
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