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EXPLAIN FORMAT=JSON: produce used_key_parts, JSON-ish output for index_merge.

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Sergei Petrunia
2014-08-14 01:12:05 +04:00
parent a9d43d70f5
commit 041e03e251
6 changed files with 274 additions and 47 deletions
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113
mysql-test/r/explain_json.result
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@ -38,13 +38,14 @@ EXPLAIN
}
}
}
# 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,
a.a + b.a* 10 + c.a * 100,
a.a + b.a* 10 + c.a * 100,
'filler'
from t0 A, t0 B, t0 C;
from t0 a, t0 b, t0 c;
explain format=json select * from t0,t1 where t1.a=t0.a;
EXPLAIN
{
@ -62,12 +63,116 @@ EXPLAIN
"access_type": "ref",
"possible_keys": ["a"],
"key": "a",
"used_key_parts": "TODO",
"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)))"
}
}
}
# 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;
drop table t0;