mirror of
https://github.com/MariaDB/server.git
synced 2025-01-16 12:02:42 +01:00
727491b72a
This includes all test changes from
"Changing all cost calculation to be given in milliseconds"
and forwards.
Some of the things that caused changes in the result files:
- As part of fixing tests, I added 'echo' to some comments to be able to
easier find out where things where wrong.
- MATERIALIZED has now a higher cost compared to X than before. Because
of this some MATERIALIZED types have changed to DEPENDEND SUBQUERY.
- Some test cases that required MATERIALIZED to repeat a bug was
changed by adding more rows to force MATERIALIZED to happen.
- 'Filtered' in SHOW EXPLAIN has in many case changed from 100.00 to
something smaller. This is because now filtered also takes into
account the smallest possible ref access and filters, even if they
where not used. Another reason for 'Filtered' being smaller is that
we now also take into account implicit filtering done for subqueries
using FIRSTMATCH.
(main.subselect_no_exists_to_in)
This is caluculated in best_access_path() and stored in records_out.
- Table orders has changed because more accurate costs.
- 'index' and 'ALL' for small tables has changed to use 'range' or
'ref' because of optimizer_scan_setup_cost.
- index can be changed to 'range' as 'range' optimizer assumes we don't
have to read the blocks from disk that range optimizer has already read.
This can be confusing in the case where there is no obvious where clause
but instead there is a hidden 'key_column > NULL' added by the optimizer.
(main.subselect_no_exists_to_in)
- Scan on primary clustered key does not report 'Using Index' anymore
(It's a table scan, not an index scan).
- For derived tables, the number of rows is now 100 instead of 2,
which can be seen in EXPLAIN.
- More tests have "Using index for group by" as the cost of this
optimization is now more correct (lower).
- A primary key could be preferred for a normal key, even if it would
access more rows, as it's faster to do 1 lokoup and 3 'index_next' on a
clustered primary key than one lookup trough a secondary.
(main.stat_tables_innodb)
Notes:
- There was a 4.7% more calls to best_extension_by_limited_search() in
the main.greedy_optimizer test. However examining the test results
it looked that the plans where slightly better (eq_ref where more
chained together) so I assume this is ok.
- I have verified a few test cases where there was notable/unexpected
changes in the plan and in all cases the new optimizer plans where
faster. (main.greedy_optimizer and some others)
122 lines
5.6 KiB
Text
122 lines
5.6 KiB
Text
drop table if exists t0, t1, t2, t3, t4;
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set optimizer_switch='semijoin=on,materialization=on';
|
|
set optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
|
|
create table t0 (a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1 as select * from t0;
|
|
# The following should use full scan on <subquery2> and it must scan 1 row:
|
|
explain select * from t0 where a in (select max(a) from t1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 1
|
|
1 PRIMARY t0 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
|
|
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 10
|
|
select * from t0 where a in (select max(a) from t1);
|
|
a
|
|
9
|
|
insert into t1 values (11);
|
|
select * from t0 where a in (select max(a) from t1);
|
|
a
|
|
delete from t1 where a=11;
|
|
insert into t0 values (NULL);
|
|
select * from t0 where a in (select max(a) from t1);
|
|
a
|
|
9
|
|
delete from t0 where a is NULL;
|
|
delete from t1;
|
|
select * from t0 where a in (select max(a) from t1);
|
|
a
|
|
insert into t0 values (NULL);
|
|
select * from t0 where a in (select max(a) from t1);
|
|
a
|
|
delete from t0 where a is NULL;
|
|
drop table t1;
|
|
create table t1 (a int, b int);
|
|
insert into t1 select a,a from t0;
|
|
create table t2 as select * from t1 where a<5;
|
|
create table t3 as select (A.a + 10*B.a) as a from t0 A, t0 B;
|
|
alter table t3 add primary key(a);
|
|
# The following should have do a full scan on <subquery2> and scan 5 rows
|
|
# (despite that subquery's join output estimate is 50 rows)
|
|
explain select * from t3 where a in (select max(t2.a) from t1, t2 group by t2.b);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 5
|
|
1 PRIMARY t3 eq_ref PRIMARY PRIMARY 8 <subquery2>.max(t2.a) 1 Using where; Using index
|
|
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using temporary
|
|
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join)
|
|
# Compare to this which really will have 50 record combinations:
|
|
explain select * from t3 where a in (select max(t2.a) from t1, t2 group by t2.b, t1.b);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 50
|
|
1 PRIMARY t3 eq_ref PRIMARY PRIMARY 8 <subquery2>.max(t2.a) 1 Using where; Using index
|
|
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using temporary
|
|
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join)
|
|
SET @save_optimizer_switch=@@optimizer_switch;
|
|
SET optimizer_switch='outer_join_with_cache=off';
|
|
# Outer joins also work:
|
|
explain select * from t3
|
|
where a in (select max(t2.a) from t1 left join t2 on t1.a=t2.a group by t2.b, t1.b);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 50
|
|
1 PRIMARY t3 eq_ref PRIMARY PRIMARY 8 <subquery2>.max(t2.a) 1 Using where; Using index
|
|
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 10 Using temporary
|
|
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using where
|
|
SET optimizer_switch=@save_optimizer_switch;
|
|
create table t4 (a int, b int, filler char(20), unique key(a,b));
|
|
insert into t4 select A.a + 10*B.a, A.a + 10*B.a, 'filler' from t0 A, t0 B;
|
|
explain select * from t0, t4 where
|
|
t4.b=t0.a and t4.a in (select max(t2.a) from t1, t2 group by t2.b);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 5
|
|
1 PRIMARY t0 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
|
|
1 PRIMARY t4 eq_ref a a 10 <subquery2>.max(t2.a),test.t0.a 1
|
|
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using temporary
|
|
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join)
|
|
insert into t4 select 100 + (B.a *100 + A.a), 100 + (B.a*100 + A.a), 'filler' from t4 A, t0 B;
|
|
explain select * from t4 where
|
|
t4.a in (select max(t2.a) from t1, t2 group by t2.b) and
|
|
t4.b in (select max(t2.a) from t1, t2 group by t2.b);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 5
|
|
1 PRIMARY <subquery3> ALL distinct_key NULL NULL NULL 5 Using join buffer (flat, BNL join)
|
|
1 PRIMARY t4 eq_ref a a 10 <subquery2>.max(t2.a),<subquery3>.max(t2.a) 1
|
|
3 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using temporary
|
|
3 MATERIALIZED t1 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join)
|
|
2 MATERIALIZED t2 ALL NULL NULL NULL NULL 5 Using temporary
|
|
2 MATERIALIZED t1 ALL NULL NULL NULL NULL 10 Using join buffer (flat, BNL join)
|
|
drop table t1,t2,t3,t4;
|
|
drop table t0;
|
|
#
|
|
# BUG#780359: Crash with get_fanout_with_deps in maria-5.3-mwl90
|
|
#
|
|
CREATE TABLE t1 (f1 int);
|
|
INSERT INTO t1 VALUES (2),(2);
|
|
CREATE TABLE t2 (f3 int);
|
|
INSERT INTO t2 VALUES (2),(2);
|
|
SELECT *
|
|
FROM t1
|
|
WHERE ( f1 ) IN (
|
|
SELECT t2.f3
|
|
FROM t2
|
|
WHERE t2.f3 = 97
|
|
AND t2.f3 = 50
|
|
GROUP BY 1
|
|
);
|
|
f1
|
|
DROP TABLE t1, t2;
|
|
#
|
|
# BUG#727183: WL#90 does not trigger with non-comma joins
|
|
#
|
|
create table t0 (a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1(a int, key(a));
|
|
insert into t1 select A.a + 10*B.a + 100*C.a from t0 A, t0 B, t0 C;
|
|
# The following must use non-merged SJ-Materialization:
|
|
explain select * from t1 X join t0 Y on X.a < Y.a where X.a in (select max(a) from t0);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <subquery2> ALL distinct_key NULL NULL NULL 1
|
|
1 PRIMARY X ref a a 5 <subquery2>.max(a) 1 Using index
|
|
1 PRIMARY Y ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
|
|
2 MATERIALIZED t0 ALL NULL NULL NULL NULL 10
|
|
drop table t0, t1;
|
|
set optimizer_switch=@save_optimizer_switch;
|