mirror of
https://github.com/MariaDB/server.git
synced 2025-10-31 15:50:51 +03:00
c91ecf9e9b
Revert commit db0917f68f, because the fix for MDEV-12696
is coming from 5.5 and 10.1 in this merge.
1585 lines
40 KiB
Plaintext
1585 lines
40 KiB
Plaintext
drop table if exists t0,t1,t2;
|
|
create table t0(a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
explain format=json select * from t0;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
explain format=json select * from t0 where 1>2;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"message": "Impossible WHERE"
|
|
}
|
|
}
|
|
}
|
|
explain format=json select * from t0 where a<3;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "t0.a < 3"
|
|
}
|
|
}
|
|
}
|
|
# Try a basic join
|
|
create table t1 (a int, b int, filler char(32), key(a));
|
|
insert into t1
|
|
select
|
|
a.a + b.a* 10 + c.a * 100,
|
|
a.a + b.a* 10 + c.a * 100,
|
|
'filler'
|
|
from t0 a, t0 b, t0 c;
|
|
explain format=json select * from t0,t1 where t1.a=t0.a;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "t0.a is not null"
|
|
},
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ref",
|
|
"possible_keys": ["a"],
|
|
"key": "a",
|
|
"key_length": "5",
|
|
"used_key_parts": ["a"],
|
|
"ref": ["test.t0.a"],
|
|
"rows": 1,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
# Try range and index_merge
|
|
create table t2 (a1 int, a2 int, b1 int, b2 int, key(a1,a2), key(b1,b2));
|
|
insert into t2 select a,a,a,a from t1;
|
|
explain format=json select * from t2 where a1<5;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "range",
|
|
"possible_keys": ["a1"],
|
|
"key": "a1",
|
|
"key_length": "5",
|
|
"used_key_parts": ["a1"],
|
|
"rows": 5,
|
|
"filtered": 100,
|
|
"index_condition": "t2.a1 < 5"
|
|
}
|
|
}
|
|
}
|
|
explain format=json select * from t2 where a1=1 or b1=2;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "index_merge",
|
|
"possible_keys": ["a1", "b1"],
|
|
"key_length": "5,5",
|
|
"index_merge": {
|
|
"sort_union": {
|
|
"range": {
|
|
"key": "a1",
|
|
"used_key_parts": ["a1"]
|
|
},
|
|
"range": {
|
|
"key": "b1",
|
|
"used_key_parts": ["b1"]
|
|
}
|
|
}
|
|
},
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "t2.a1 = 1 or t2.b1 = 2"
|
|
}
|
|
}
|
|
}
|
|
explain format=json select * from t2 where a1=1 or (b1=2 and b2=3);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "index_merge",
|
|
"possible_keys": ["a1", "b1"],
|
|
"key_length": "5,10",
|
|
"index_merge": {
|
|
"sort_union": {
|
|
"range": {
|
|
"key": "a1",
|
|
"used_key_parts": ["a1"]
|
|
},
|
|
"range": {
|
|
"key": "b1",
|
|
"used_key_parts": ["b1", "b2"]
|
|
}
|
|
}
|
|
},
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "t2.a1 = 1 or t2.b1 = 2 and t2.b2 = 3"
|
|
}
|
|
}
|
|
}
|
|
explain format=json select * from t2 where (a1=1 and a2=1) or
|
|
(b1=2 and b2=1);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "index_merge",
|
|
"possible_keys": ["a1", "b1"],
|
|
"key_length": "10,10",
|
|
"index_merge": {
|
|
"union": {
|
|
"range": {
|
|
"key": "a1",
|
|
"used_key_parts": ["a1", "a2"]
|
|
},
|
|
"range": {
|
|
"key": "b1",
|
|
"used_key_parts": ["b1", "b2"]
|
|
}
|
|
}
|
|
},
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "t2.a1 = 1 and t2.a2 = 1 or t2.b1 = 2 and t2.b2 = 1"
|
|
}
|
|
}
|
|
}
|
|
# Try ref access on two key components
|
|
explain format=json select * from t0,t2 where t2.b1=t0.a and t2.b2=4;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "t0.a is not null"
|
|
},
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "ref",
|
|
"possible_keys": ["b1"],
|
|
"key": "b1",
|
|
"key_length": "10",
|
|
"used_key_parts": ["b1", "b2"],
|
|
"ref": ["test.t0.a", "const"],
|
|
"rows": 1,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
drop table t1,t2;
|
|
#
|
|
# Try a UNION
|
|
#
|
|
explain format=json select * from t0 A union select * from t0 B;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"union_result": {
|
|
"table_name": "<union1,2>",
|
|
"access_type": "ALL",
|
|
"query_specifications": [
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "A",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
},
|
|
{
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"table": {
|
|
"table_name": "B",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
}
|
|
explain format=json select * from t0 A union all select * from t0 B;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"union_result": {
|
|
"table_name": "<union1,2>",
|
|
"access_type": "ALL",
|
|
"query_specifications": [
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "A",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
},
|
|
{
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"table": {
|
|
"table_name": "B",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
}
|
|
#
|
|
# Subqueries
|
|
#
|
|
create table t1 (a int, b int);
|
|
insert into t1 select a,a from t0;
|
|
explain format=json select a, a > (select max(b) from t1 where t1.b=t0.a) from t0;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
},
|
|
"subqueries": [
|
|
{
|
|
"expression_cache": {
|
|
"state": "uninitialized",
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "t1.b = t0.a"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
explain format=json
|
|
select * from t0 where
|
|
a > (select max(b) from t1 where t1.b=t0.a) or a < 3 ;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "t0.a > (subquery#2) or t0.a < 3"
|
|
},
|
|
"subqueries": [
|
|
{
|
|
"expression_cache": {
|
|
"state": "uninitialized",
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "t1.b = t0.a"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
drop table t1;
|
|
#
|
|
# Join buffering
|
|
#
|
|
create table t1 (a int, b int);
|
|
insert into t1 select tbl1.a+10*tbl2.a, tbl1.a+10*tbl2.a from t0 tbl1, t0 tbl2;
|
|
explain format=json
|
|
select * from t1 tbl1, t1 tbl2 where tbl1.a=tbl2.a and tbl1.b < 3 and tbl2.b < 5;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "tbl1",
|
|
"access_type": "ALL",
|
|
"rows": 100,
|
|
"filtered": 100,
|
|
"attached_condition": "tbl1.b < 3"
|
|
},
|
|
"block-nl-join": {
|
|
"table": {
|
|
"table_name": "tbl2",
|
|
"access_type": "ALL",
|
|
"rows": 100,
|
|
"filtered": 100,
|
|
"attached_condition": "tbl2.b < 5"
|
|
},
|
|
"buffer_type": "flat",
|
|
"buffer_size": "256Kb",
|
|
"join_type": "BNL",
|
|
"attached_condition": "tbl2.a = tbl1.a"
|
|
}
|
|
}
|
|
}
|
|
drop table t1;
|
|
#
|
|
# Single-table UPDATE/DELETE, INSERT
|
|
#
|
|
explain format=json delete from t0;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"message": "Deleting all rows"
|
|
}
|
|
}
|
|
}
|
|
explain format=json delete from t0 where 1 > 2;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"message": "Impossible WHERE"
|
|
}
|
|
}
|
|
}
|
|
explain format=json delete from t0 where a < 3;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"delete": 1,
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"attached_condition": "t0.a < 3"
|
|
}
|
|
}
|
|
}
|
|
explain format=json update t0 set a=3 where a in (2,3,4);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"update": 1,
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"attached_condition": "t0.a in (2,3,4)"
|
|
}
|
|
}
|
|
}
|
|
explain format=json insert into t0 values (1);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t0"
|
|
}
|
|
}
|
|
}
|
|
create table t1 like t0;
|
|
explain format=json insert into t1 values ((select max(a) from t0));
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1"
|
|
},
|
|
"subqueries": [
|
|
{
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
drop table t1;
|
|
#
|
|
# A derived table
|
|
#
|
|
create table t1 (a int, b int);
|
|
insert into t1 select a,a from t0;
|
|
explain format=json
|
|
select * from (select a, count(*) as cnt from t1 group by a) as tbl
|
|
where cnt>0;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "<derived2>",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "tbl.cnt > 0",
|
|
"materialized": {
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"having_condition": "cnt > 0",
|
|
"filesort": {
|
|
"sort_key": "t1.a",
|
|
"temporary_table": {
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
explain format=json
|
|
select * from (select a, count(*) as cnt from t1 group by a) as tbl1, t1 as
|
|
tbl2 where cnt=tbl2.a;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "tbl2",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "tbl2.a is not null"
|
|
},
|
|
"table": {
|
|
"table_name": "<derived2>",
|
|
"access_type": "ref",
|
|
"possible_keys": ["key0"],
|
|
"key": "key0",
|
|
"key_length": "8",
|
|
"used_key_parts": ["cnt"],
|
|
"ref": ["test.tbl2.a"],
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "tbl1.cnt = tbl2.a",
|
|
"materialized": {
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"filesort": {
|
|
"sort_key": "t1.a",
|
|
"temporary_table": {
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
#
|
|
# Non-merged semi-join (aka JTBM)
|
|
#
|
|
explain format=json
|
|
select * from t1 where a in (select max(a) from t1 group by b);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "t1.a is not null"
|
|
},
|
|
"table": {
|
|
"table_name": "<subquery2>",
|
|
"access_type": "eq_ref",
|
|
"possible_keys": ["distinct_key"],
|
|
"key": "distinct_key",
|
|
"key_length": "4",
|
|
"used_key_parts": ["max(a)"],
|
|
"ref": ["test.t1.a"],
|
|
"rows": 1,
|
|
"filtered": 100,
|
|
"materialized": {
|
|
"unique": 1,
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"temporary_table": {
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
#
|
|
# Semi-join Materialization
|
|
#
|
|
create table t2 like t1;
|
|
insert into t2 select * from t1;
|
|
explain format=json
|
|
select * from t1,t2 where t1.a in ( select a from t0);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"const_condition": "1",
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
},
|
|
"table": {
|
|
"table_name": "<subquery2>",
|
|
"access_type": "eq_ref",
|
|
"possible_keys": ["distinct_key"],
|
|
"key": "distinct_key",
|
|
"key_length": "4",
|
|
"used_key_parts": ["a"],
|
|
"ref": ["func"],
|
|
"rows": 1,
|
|
"filtered": 100,
|
|
"materialized": {
|
|
"unique": 1,
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
},
|
|
"block-nl-join": {
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
},
|
|
"buffer_type": "flat",
|
|
"buffer_size": "256Kb",
|
|
"join_type": "BNL"
|
|
}
|
|
}
|
|
}
|
|
#
|
|
# First-Match
|
|
#
|
|
explain
|
|
select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t2 ALL NULL NULL NULL NULL 10
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 10 Using where; FirstMatch(t2); Using join buffer (flat, BNL join)
|
|
explain format=json
|
|
select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
},
|
|
"block-nl-join": {
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"first_match": "t2"
|
|
},
|
|
"buffer_type": "flat",
|
|
"buffer_size": "256Kb",
|
|
"join_type": "BNL",
|
|
"attached_condition": "t1.b = t2.b and t1.a = t2.a"
|
|
}
|
|
}
|
|
}
|
|
#
|
|
# Duplicate Weedout
|
|
#
|
|
set @tmp= @@optimizer_switch;
|
|
set optimizer_switch='firstmatch=off';
|
|
explain
|
|
select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t2 ALL NULL NULL NULL NULL 10
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 10 Using where; Start temporary; End temporary; Using join buffer (flat, BNL join)
|
|
explain format=json
|
|
select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
},
|
|
"duplicates_removal": {
|
|
"block-nl-join": {
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
},
|
|
"buffer_type": "flat",
|
|
"buffer_size": "256Kb",
|
|
"join_type": "BNL",
|
|
"attached_condition": "t1.b = t2.b and t1.a = t2.a"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
set optimizer_switch=@tmp;
|
|
drop table t1,t2;
|
|
#
|
|
# MRR for range access (no BKA, just MRR)
|
|
#
|
|
create table t1 (a int, b int, key(a));
|
|
insert into t1 select tbl1.a+10*tbl2.a, 12345 from t0 tbl1, t0 tbl2;
|
|
set @tmp= @@optimizer_switch;
|
|
set optimizer_switch='mrr=on,mrr_sort_keys=on';
|
|
explain format=json select * from t1 where a < 3;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "range",
|
|
"possible_keys": ["a"],
|
|
"key": "a",
|
|
"key_length": "5",
|
|
"used_key_parts": ["a"],
|
|
"rows": 1,
|
|
"filtered": 100,
|
|
"index_condition": "t1.a < 3",
|
|
"mrr_type": "Rowid-ordered scan"
|
|
}
|
|
}
|
|
}
|
|
# 'Range checked for each record'
|
|
set optimizer_switch=@tmp;
|
|
explain format=json
|
|
select * from t1 tbl1, t1 tbl2 where tbl2.a < tbl1.b;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "tbl1",
|
|
"access_type": "ALL",
|
|
"rows": 100,
|
|
"filtered": 100
|
|
},
|
|
"range-checked-for-each-record": {
|
|
"keys": ["a"],
|
|
"table": {
|
|
"table_name": "tbl2",
|
|
"access_type": "ALL",
|
|
"possible_keys": ["a"],
|
|
"rows": 100,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
drop table t1;
|
|
drop table t0;
|
|
#
|
|
# MDEV-7265: "Full scan on NULL key", the join case
|
|
#
|
|
CREATE TABLE t1 (a INT, KEY(a));
|
|
INSERT INTO t1 VALUES (1),(2);
|
|
CREATE TABLE t2 (b INT);
|
|
INSERT INTO t2 VALUES (3),(4);
|
|
EXPLAIN FORMAT=JSON SELECT * FROM t1 AS outer_t1 WHERE a <> ALL ( SELECT a FROM t1, t2 WHERE b <> outer_t1.a );
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "outer_t1",
|
|
"access_type": "index",
|
|
"key": "a",
|
|
"key_length": "5",
|
|
"used_key_parts": ["a"],
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "!<in_optimizer>(outer_t1.a,<exists>(subquery#2))",
|
|
"using_index": true
|
|
},
|
|
"subqueries": [
|
|
{
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"having_condition": "trigcond(t1.a is null)",
|
|
"full-scan-on-null_key": {
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ref_or_null",
|
|
"possible_keys": ["a"],
|
|
"key": "a",
|
|
"key_length": "5",
|
|
"used_key_parts": ["a"],
|
|
"ref": ["func"],
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "trigcond(<cache>(outer_t1.a) = t1.a or t1.a is null)",
|
|
"using_index": true
|
|
}
|
|
},
|
|
"block-nl-join": {
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "ALL",
|
|
"rows": 2,
|
|
"filtered": 100
|
|
},
|
|
"buffer_type": "flat",
|
|
"buffer_size": "256Kb",
|
|
"join_type": "BNL",
|
|
"attached_condition": "t2.b <> outer_t1.a"
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
DROP TABLE t1,t2;
|
|
#
|
|
# Join's constant expression
|
|
#
|
|
create table t0(a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1(a int, b int);
|
|
insert into t1 select tbl1.a+10*tbl2.a, 1234 from t0 tbl1, t0 tbl2;
|
|
explain format=json
|
|
select * from t0
|
|
where
|
|
20000 > all (select max(tbl1.a + tbl2.a)
|
|
from t1 tbl1, t1 tbl2 where tbl1.b=tbl2.b);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"const_condition": "<not>(<in_optimizer>(20000,<max>(subquery#2) >= 20000))",
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
},
|
|
"subqueries": [
|
|
{
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"table": {
|
|
"table_name": "tbl1",
|
|
"access_type": "ALL",
|
|
"rows": 100,
|
|
"filtered": 100
|
|
},
|
|
"block-nl-join": {
|
|
"table": {
|
|
"table_name": "tbl2",
|
|
"access_type": "ALL",
|
|
"rows": 100,
|
|
"filtered": 100
|
|
},
|
|
"buffer_type": "flat",
|
|
"buffer_size": "256Kb",
|
|
"join_type": "BNL",
|
|
"attached_condition": "tbl2.b = tbl1.b"
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
drop table t1;
|
|
drop table t0;
|
|
#
|
|
# MDEV-7264: Assertion `0' failed in subselect_engine::get_identifier() on EXPLAIN JSON
|
|
#
|
|
CREATE TABLE t1 (a INT);
|
|
INSERT INTO t1 VALUES (1),(2);
|
|
CREATE TABLE t2 (b INT);
|
|
INSERT INTO t2 VALUES (3),(4);
|
|
EXPLAIN FORMAT=JSON SELECT * FROM t1 WHERE a <> ALL ( SELECT b FROM t2 );
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "!<in_optimizer>(t1.a,t1.a in (subquery#2))"
|
|
},
|
|
"subqueries": [
|
|
{
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "ALL",
|
|
"rows": 2,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
DROP TABLE t1, t2;
|
|
#
|
|
# MDEV-7927: Server crashes in in Time_and_counter_tracker::incr_loops
|
|
#
|
|
CREATE TABLE t1 (i INT);
|
|
INSERT INTO t1 VALUES (1),(2);
|
|
EXPLAIN SELECT * FROM t1 WHERE 3 IN ( SELECT 4 UNION SELECT 5 );
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
DROP TABLE t1;
|
|
#
|
|
# MDEV-7860: EXPLAIN FORMAT=JSON crashes for loose scan query
|
|
#
|
|
create table t2(a int);
|
|
insert into t2 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1 (a int, b int, c int, d int, key(a,b,c));
|
|
insert into t1 select A.a, B.a, C.a, D.a from t2 A, t2 B, t2 C, t2 D;
|
|
explain select count(distinct b) from t1 group by a;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range NULL a 10 NULL 101 Using index for group-by
|
|
explain format=json select count(distinct b) from t1 group by a;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "range",
|
|
"key": "a",
|
|
"key_length": "10",
|
|
"used_key_parts": ["a", "b"],
|
|
"rows": 101,
|
|
"filtered": 100,
|
|
"using_index_for_group_by": true
|
|
}
|
|
}
|
|
}
|
|
analyze format=json select count(distinct b) from t1 group by a;
|
|
ANALYZE
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"r_loops": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "range",
|
|
"key": "a",
|
|
"key_length": "10",
|
|
"used_key_parts": ["a", "b"],
|
|
"r_loops": 1,
|
|
"rows": 101,
|
|
"r_rows": 100,
|
|
"r_total_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": 100,
|
|
"using_index_for_group_by": true
|
|
}
|
|
}
|
|
}
|
|
drop table t1,t2;
|
|
#
|
|
# Try both variants of LooseScan (data/queries borrowed from group_min_max.test)
|
|
#
|
|
create table t1 (
|
|
a1 char(64), a2 char(64), b char(16), c char(16) not null, d char(16), dummy char(248) default ' '
|
|
);
|
|
insert into t1 (a1, a2, b, c, d) values
|
|
('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
|
|
('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
|
|
('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
|
|
('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
|
|
('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
|
|
('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
|
|
('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
|
|
('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
|
|
('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
|
|
('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
|
|
('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
|
|
('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4'),
|
|
('d','a','a','a411','xy1'),('d','a','a','b411','xy2'),('d','a','a','c411','xy3'),('d','a','a','d411','xy4'),
|
|
('d','a','b','e412','xy1'),('d','a','b','f412','xy2'),('d','a','b','g412','xy3'),('d','a','b','h412','xy4'),
|
|
('d','b','a','i421','xy1'),('d','b','a','j421','xy2'),('d','b','a','k421','xy3'),('d','b','a','l421','xy4'),
|
|
('d','b','b','m422','xy1'),('d','b','b','n422','xy2'),('d','b','b','o422','xy3'),('d','b','b','p422','xy4'),
|
|
('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
|
|
('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
|
|
('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
|
|
('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
|
|
('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
|
|
('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
|
|
('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
|
|
('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
|
|
('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
|
|
('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
|
|
('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
|
|
('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4'),
|
|
('d','a','a','a411','xy1'),('d','a','a','b411','xy2'),('d','a','a','c411','xy3'),('d','a','a','d411','xy4'),
|
|
('d','a','b','e412','xy1'),('d','a','b','f412','xy2'),('d','a','b','g412','xy3'),('d','a','b','h412','xy4'),
|
|
('d','b','a','i421','xy1'),('d','b','a','j421','xy2'),('d','b','a','k421','xy3'),('d','b','a','l421','xy4'),
|
|
('d','b','b','m422','xy1'),('d','b','b','n422','xy2'),('d','b','b','o422','xy3'),('d','b','b','p422','xy4');
|
|
create index idx_t1_0 on t1 (a1);
|
|
create index idx_t1_1 on t1 (a1,a2,b,c);
|
|
create index idx_t1_2 on t1 (a1,a2,b);
|
|
analyze table t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Table is already up to date
|
|
explain select count(distinct a1,a2,b) from t1 where (a2 >= 'b') and (b = 'a');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range NULL idx_t1_1 147 NULL 17 Using where; Using index for group-by
|
|
explain select count(distinct a1,a2,b,c) from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range NULL idx_t1_1 163 NULL 65 Using where; Using index for group-by (scanning)
|
|
explain format=json select count(distinct a1,a2,b) from t1 where (a2 >= 'b') and (b = 'a');
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "range",
|
|
"key": "idx_t1_1",
|
|
"key_length": "147",
|
|
"used_key_parts": ["a1", "a2", "b"],
|
|
"rows": 17,
|
|
"filtered": 100,
|
|
"attached_condition": "t1.b = 'a' and t1.a2 >= 'b'",
|
|
"using_index_for_group_by": true
|
|
}
|
|
}
|
|
}
|
|
explain format=json select count(distinct a1,a2,b,c) from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "range",
|
|
"key": "idx_t1_1",
|
|
"key_length": "163",
|
|
"used_key_parts": ["a1", "a2", "b", "c"],
|
|
"rows": 65,
|
|
"filtered": 100,
|
|
"attached_condition": "t1.b = 'a' and t1.c = 'i121' and t1.a2 >= 'b'",
|
|
"using_index_for_group_by": "scanning"
|
|
}
|
|
}
|
|
}
|
|
drop table t1;
|
|
#
|
|
# MDEV-8786 Wrong result for SELECT FORMAT=JSON * FROM t1 WHERE a=_latin1 0xDF
|
|
#
|
|
CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET latin1);
|
|
INSERT INTO t1 VALUES ('a'),('b');
|
|
EXPLAIN FORMAT=JSON SELECT * FROM t1 WHERE a=_latin1 0xDF;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "t1.a = _latin1'\xDF'"
|
|
}
|
|
}
|
|
}
|
|
DROP TABLE t1;
|
|
#
|
|
# MDEV-8785 Wrong results for EXPLAIN EXTENDED...WHERE NULLIF(latin1_col, _utf8'a' COLLATE utf8_bin) IS NOT NULL
|
|
#
|
|
CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET latin1);
|
|
INSERT INTO t1 VALUES ('a'),('A');
|
|
EXPLAIN FORMAT=JSON SELECT * FROM t1 WHERE NULLIF(a,_utf8'a' COLLATE utf8_bin);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "(case when convert(t1.a using utf8) = <cache>(_utf8'a' collate utf8_bin) then NULL else t1.a end)"
|
|
}
|
|
}
|
|
}
|
|
DROP TABLE t1;
|
|
#
|
|
# MDEV-7970: EXPLAIN FORMAT=JSON does not print HAVING
|
|
#
|
|
create table t0(a int);
|
|
insert into t0 values (0),(1),(2),(3);
|
|
create table t1(a int);
|
|
insert into t1 select A.a + B.a* 10 + C.a * 100 from t0 A, t0 B, t0 C;
|
|
create table t2 (
|
|
a int,
|
|
b int,
|
|
key (a)
|
|
);
|
|
insert into t2 select A.a*1000 + B.a, A.a*1000 + B.a from t0 A, t1 B;
|
|
# normal HAVING
|
|
explain format=json select a, max(b) as TOP from t2 group by a having TOP > a;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"having_condition": "TOP > t2.a",
|
|
"filesort": {
|
|
"sort_key": "t2.a",
|
|
"temporary_table": {
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "ALL",
|
|
"rows": 256,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
# HAVING is always TRUE (not printed)
|
|
explain format=json select a, max(b) as TOP from t2 group by a having 1<>2;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"filesort": {
|
|
"sort_key": "t2.a",
|
|
"temporary_table": {
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "ALL",
|
|
"rows": 256,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
# HAVING is always FALSE (intercepted by message)
|
|
explain format=json select a, max(b) as TOP from t2 group by a having 1=2;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"message": "Impossible HAVING"
|
|
}
|
|
}
|
|
}
|
|
# HAVING is absent
|
|
explain format=json select a, max(b) as TOP from t2 group by a;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"filesort": {
|
|
"sort_key": "t2.a",
|
|
"temporary_table": {
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "ALL",
|
|
"rows": 256,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
drop table t0, t1, t2;
|
|
#
|
|
# MDEV-8829: Assertion `0' failed in Explain_table_access::tag_to_json
|
|
#
|
|
# Check ET_CONST_ROW_NOT_FOUND
|
|
create table t1 (i int) engine=myisam;
|
|
explain
|
|
select * from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 system NULL NULL NULL NULL 0 const row not found
|
|
explain format=json
|
|
select * from t1;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "system",
|
|
"rows": 0,
|
|
"filtered": 0,
|
|
"const_row_not_found": true
|
|
}
|
|
}
|
|
}
|
|
analyze format=json
|
|
select * from t1;
|
|
ANALYZE
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"message": "no matching row in const table"
|
|
}
|
|
}
|
|
}
|
|
drop table t1;
|
|
# Check ET_IMPOSSIBLE_ON_CONDITION
|
|
create table t1 (a int);
|
|
create table t2 (pk int primary key);
|
|
insert into t1 values (1),(2);
|
|
insert into t2 values (1),(2);
|
|
explain
|
|
select * from t1 left join t2 on t2.pk > 10 and t2.pk < 0;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t2 const PRIMARY NULL NULL NULL 1 Impossible ON condition
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
|
|
explain format=json
|
|
select * from t1 left join t2 on t2.pk > 10 and t2.pk < 0;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"const_condition": "1",
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "const",
|
|
"possible_keys": ["PRIMARY"],
|
|
"rows": 1,
|
|
"filtered": 100,
|
|
"impossible_on_condition": true
|
|
},
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 2,
|
|
"filtered": 100
|
|
}
|
|
}
|
|
}
|
|
analyze format=json
|
|
select * from t1 left join t2 on t2.pk > 10 and t2.pk < 0;
|
|
ANALYZE
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"r_loops": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"const_condition": "1",
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "const",
|
|
"possible_keys": ["PRIMARY"],
|
|
"r_loops": 0,
|
|
"rows": 1,
|
|
"r_rows": null,
|
|
"filtered": 100,
|
|
"r_filtered": null,
|
|
"impossible_on_condition": true
|
|
},
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"r_loops": 1,
|
|
"rows": 2,
|
|
"r_rows": 2,
|
|
"r_total_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": 100
|
|
}
|
|
}
|
|
}
|
|
# Check ET_NOT_EXISTS:
|
|
explain
|
|
select * from t1 left join t2 on t2.pk=t1.a where t2.pk is null;
|
|
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 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 Using where; Using index; Not exists
|
|
explain format=json
|
|
select * from t1 left join t2 on t2.pk=t1.a where t2.pk is null;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 2,
|
|
"filtered": 100
|
|
},
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "eq_ref",
|
|
"possible_keys": ["PRIMARY"],
|
|
"key": "PRIMARY",
|
|
"key_length": "4",
|
|
"used_key_parts": ["pk"],
|
|
"ref": ["test.t1.a"],
|
|
"rows": 1,
|
|
"filtered": 100,
|
|
"attached_condition": "trigcond(t2.pk is null) and trigcond(trigcond(t1.a is not null))",
|
|
"using_index": true,
|
|
"not_exists": true
|
|
}
|
|
}
|
|
}
|
|
analyze format=json
|
|
select * from t1 left join t2 on t2.pk=t1.a where t2.pk is null;
|
|
ANALYZE
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"r_loops": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"r_loops": 1,
|
|
"rows": 2,
|
|
"r_rows": 2,
|
|
"r_total_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": 100
|
|
},
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "eq_ref",
|
|
"possible_keys": ["PRIMARY"],
|
|
"key": "PRIMARY",
|
|
"key_length": "4",
|
|
"used_key_parts": ["pk"],
|
|
"ref": ["test.t1.a"],
|
|
"r_loops": 2,
|
|
"rows": 1,
|
|
"r_rows": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": 100,
|
|
"attached_condition": "trigcond(t2.pk is null) and trigcond(trigcond(t1.a is not null))",
|
|
"using_index": true,
|
|
"not_exists": true
|
|
}
|
|
}
|
|
}
|
|
# Check ET_DISTINCT
|
|
explain
|
|
select distinct t1.a from t1 join t2 on t2.pk=t1.a;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 2 Using where; Using temporary
|
|
1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 Using index; Distinct
|
|
explain format=json
|
|
select distinct t1.a from t1 join t2 on t2.pk=t1.a;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"temporary_table": {
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 2,
|
|
"filtered": 100,
|
|
"attached_condition": "t1.a is not null"
|
|
},
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "eq_ref",
|
|
"possible_keys": ["PRIMARY"],
|
|
"key": "PRIMARY",
|
|
"key_length": "4",
|
|
"used_key_parts": ["pk"],
|
|
"ref": ["test.t1.a"],
|
|
"rows": 1,
|
|
"filtered": 100,
|
|
"using_index": true,
|
|
"distinct": true
|
|
}
|
|
}
|
|
}
|
|
}
|
|
analyze format=json
|
|
select distinct t1.a from t1 join t2 on t2.pk=t1.a;
|
|
ANALYZE
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"r_loops": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"temporary_table": {
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"r_loops": 1,
|
|
"rows": 2,
|
|
"r_rows": 2,
|
|
"r_total_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": 100,
|
|
"attached_condition": "t1.a is not null"
|
|
},
|
|
"table": {
|
|
"table_name": "t2",
|
|
"access_type": "eq_ref",
|
|
"possible_keys": ["PRIMARY"],
|
|
"key": "PRIMARY",
|
|
"key_length": "4",
|
|
"used_key_parts": ["pk"],
|
|
"ref": ["test.t1.a"],
|
|
"r_loops": 2,
|
|
"rows": 1,
|
|
"r_rows": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": 100,
|
|
"using_index": true,
|
|
"distinct": true
|
|
}
|
|
}
|
|
}
|
|
}
|
|
drop table t1,t2;
|
|
# Check ET_USING_INDEX_CONDITION_BKA
|
|
create table t1(a int);
|
|
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t2(a int);
|
|
insert into t2 select A.a + B.a* 10 + C.a * 100 from t1 A, t1 B, t1 C;
|
|
create table t3(a int, b int);
|
|
insert into t3 select a,a from t1;
|
|
create table t4(a int, b int, c int, filler char(100), key (a,b));
|
|
insert into t4 select a,a,a, 'filler-data' from t2;
|
|
set @tmp_optimizer_switch=@@optimizer_switch;
|
|
set @tmp_join_cache_level=@@join_cache_level;
|
|
set optimizer_switch='mrr=on';
|
|
set join_cache_level=6;
|
|
explain
|
|
select * from t3,t4 where t3.a=t4.a and (t4.b+1 <= t3.b+1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t3 ALL NULL NULL NULL NULL 10 Using where
|
|
1 SIMPLE t4 ref a a 5 test.t3.a 1 Using index condition(BKA); Using join buffer (flat, BKA join); Rowid-ordered scan
|
|
explain format=json
|
|
select * from t3,t4 where t3.a=t4.a and (t4.b+1 <= t3.b+1);
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t3",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "t3.a is not null"
|
|
},
|
|
"block-nl-join": {
|
|
"table": {
|
|
"table_name": "t4",
|
|
"access_type": "ref",
|
|
"possible_keys": ["a"],
|
|
"key": "a",
|
|
"key_length": "5",
|
|
"used_key_parts": ["a"],
|
|
"ref": ["test.t3.a"],
|
|
"rows": 1,
|
|
"filtered": 100,
|
|
"index_condition_bka": "t4.b + 1 <= t3.b + 1"
|
|
},
|
|
"buffer_type": "flat",
|
|
"buffer_size": "256Kb",
|
|
"join_type": "BKA",
|
|
"mrr_type": "Rowid-ordered scan"
|
|
}
|
|
}
|
|
}
|
|
analyze format=json
|
|
select * from t3,t4 where t3.a=t4.a and (t4.b+1 <= t3.b+1);
|
|
ANALYZE
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"r_loops": 1,
|
|
"r_total_time_ms": "REPLACED",
|
|
"table": {
|
|
"table_name": "t3",
|
|
"access_type": "ALL",
|
|
"r_loops": 1,
|
|
"rows": 10,
|
|
"r_rows": 10,
|
|
"r_total_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": 100,
|
|
"attached_condition": "t3.a is not null"
|
|
},
|
|
"block-nl-join": {
|
|
"table": {
|
|
"table_name": "t4",
|
|
"access_type": "ref",
|
|
"possible_keys": ["a"],
|
|
"key": "a",
|
|
"key_length": "5",
|
|
"used_key_parts": ["a"],
|
|
"ref": ["test.t3.a"],
|
|
"r_loops": 0,
|
|
"rows": 1,
|
|
"r_rows": null,
|
|
"r_total_time_ms": "REPLACED",
|
|
"filtered": 100,
|
|
"r_filtered": null,
|
|
"index_condition_bka": "t4.b + 1 <= t3.b + 1"
|
|
},
|
|
"buffer_type": "flat",
|
|
"buffer_size": "256Kb",
|
|
"join_type": "BKA",
|
|
"mrr_type": "Rowid-ordered scan",
|
|
"r_filtered": 100
|
|
}
|
|
}
|
|
}
|
|
set optimizer_switch=@tmp_optimizer_switch;
|
|
set join_cache_level=@tmp_join_cache_level;
|
|
drop table t1,t2,t3,t4;
|
|
#
|
|
# MDEV-9652: EXPLAIN FORMAT=JSON should show outer_ref_cond
|
|
#
|
|
create table t0(a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1 (a int, b int);
|
|
insert into t1 select a,a from t0;
|
|
explain format=json
|
|
select a, (select max(a) from t1 where t0.a<5 and t1.b<t0.a) from t0;
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t0",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100
|
|
},
|
|
"subqueries": [
|
|
{
|
|
"expression_cache": {
|
|
"state": "uninitialized",
|
|
"query_block": {
|
|
"select_id": 2,
|
|
"outer_ref_condition": "t0.a < 5",
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "ALL",
|
|
"rows": 10,
|
|
"filtered": 100,
|
|
"attached_condition": "t1.b < t0.a"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
drop table t0,t1;
|