mariadb/mysql-test/t/explain_json.test

#
# EXPLAIN FORMAT=JSON tests. These are tests developed for MariaDB.
#
--disable_warnings
drop table if exists t0,t1,t2;
--enable_warnings

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 format=json select * from t0 where 1>2;

explain format=json select * from t0 where a<3;

--echo # 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;

--echo # 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 format=json select * from t2 where a1=1 or b1=2;
explain format=json select * from t2 where a1=1 or (b1=2 and b2=3);

explain format=json select * from t2 where (a1=1 and a2=1) or 
                                           (b1=2 and b2=1);

--echo # Try ref access on two key components

explain format=json select * from t0,t2 where t2.b1=t0.a and t2.b2=4;

drop table t1,t2;

--echo #
--echo # Try a UNION
--echo #
explain format=json select * from t0 A union     select * from t0 B;
explain format=json select * from t0 A union all select * from t0 B;

--echo #
--echo # Subqueries
--echo #
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 format=json 
select * from t0 where 
  a > (select max(b) from t1 where t1.b=t0.a) or a < 3 ;

drop table t1;

--echo #
--echo # Join buffering
--echo #
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;

drop table t1;

--echo #
--echo # Single-table UPDATE/DELETE, INSERT
--echo #
explain format=json delete from t0;
explain format=json delete from t0 where 1 > 2;

explain format=json delete from t0 where a < 3;

explain format=json update t0 set a=3 where a in (2,3,4);

explain format=json insert into t0 values (1);

create table t1 like t0;
explain format=json insert into t1 values ((select max(a) from t0));

drop table t1;

--echo #
--echo # A derived table
--echo #
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 format=json
select * from (select a, count(*) as cnt from t1 group by a) as tbl1, t1 as
tbl2 where cnt=tbl2.a;

--echo #
--echo # Non-merged semi-join (aka JTBM)
--echo #
explain format=json 
select * from t1 where a in (select max(a) from t1 group by b);

--echo #
--echo # Semi-join Materialization
--echo #
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);

--echo # 
--echo # First-Match
--echo # 
explain
select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
explain format=json
select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);

--echo # 
--echo # Duplicate Weedout
--echo # 
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);
explain format=json
select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
set optimizer_switch=@tmp;

drop table t1,t2;

--echo #
--echo # MRR for range access (no BKA, just MRR)
--echo #
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;

--echo # 'Range checked for each record'
set optimizer_switch=@tmp;
explain format=json
select * from t1 tbl1, t1 tbl2 where tbl2.a < tbl1.b;

drop table t1;
drop table t0;

--echo #
--echo # MDEV-7265: "Full scan on NULL key", the join case
--echo #

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 );

DROP TABLE t1,t2;

--echo #
--echo # Join's constant expression
--echo #
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);

drop table t1;
drop table t0;

--echo # 
--echo # MDEV-7264: Assertion `0' failed in subselect_engine::get_identifier() on EXPLAIN JSON
--echo # 
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 );
DROP TABLE t1, t2;