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EXPLAIN JSON: Print out the "expensive constant condition" attached to joins.

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This commit is contained in:
Sergei Petrunia
2014-12-06 19:27:42 +03:00
parent 5ee1c25fa8
commit dc259324d7
5 changed files with 104 additions and 5 deletions
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52
mysql-test/r/explain_json.result
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@ -551,6 +551,7 @@ EXPLAIN
{
"query_block": {
"select_id": 1,
"const_condition": "1",
"table": {
"table_name": "t1",
"access_type": "ALL",
@ -778,3 +779,54 @@ EXPLAIN
}
}
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",
"join_type": "BNL",
"attached_condition": "(tbl2.b = tbl1.b)"
}
}
}
]
}
}
drop table t1;
drop table t0;