set sql_mode=oracle;
use test;
create or replace table tab_delete(c1 integer not null,c2 integer not null) engine=InnoDb;
create index tab_delete_c1 on tab_delete(c1);
create or replace view view_delete as select * from tab_delete where c1 in (0,1);
CREATE or replace PROCEDURE gendata(a int, count int ) AS
i INT:=0;
BEGIN
FOR i IN 1 .. count
LOOP
insert into tab_delete values (a,i);
END LOOP;
END;
/
create or replace trigger trg after delete on tab_delete for each row
begin
declare c int;
begin
if old.c1 = 1 then
select count(*) into c from tab_delete where c1!=old.c1;
SIGNAL SQLSTATE '45000' set table_name=c;
end if;
end;
end;
/
set @count=500;
call gendata(0,@count);
call gendata(1,50);
call gendata(2,20);
call gendata(3,20);
commit;
#
# Delete with limit (quick select - range acces)
#
start transaction;
delete from tab_delete where (select count(*) from tab_delete b where b.c1=tab_delete.c1) = 500 limit 1;
affected rows: 1
delete from tab_delete where (select count(*) from tab_delete b where b.c1=tab_delete.c1) = 500 limit 1;
affected rows: 0
select count(*) from view_delete where c1=0;
count(*)
499
rollback;
#
# Delete
#
start transaction;
delete from tab_delete where (select count(*) from tab_delete b where b.c1=tab_delete.c1) = 500 ;
affected rows: 500
rollback;
#
# Delete with exists
#
start transaction;
select count(*) from view_delete where c1=2;
count(*)
0
delete from tab_delete where c1=2 and exists(select 'x' from tab_delete b where b.c2<10);
affected rows: 20
delete from tab_delete where c1=2 and exists(select 'x' from tab_delete b where b.c2<10);
affected rows: 0
select count(*) from view_delete where c1=2;
count(*)
0
rollback;
#
# Delete throw a view with limit (range access)
#
start transaction;
# Acces by range (quick_select), initied = INDEX
# +------+--------------------+------------+-------+---------------+---------------+---------+--------------------+------+-------------+
# | id   | select_type        | table      | type  | possible_keys | key           | key_len | ref                | rows | Extra       |
# +------+--------------------+------------+-------+---------------+---------------+---------+--------------------+------+-------------+
# |    1 | PRIMARY            | tab_delete | range | tab_delete_c1 | tab_delete_c1 | 4       | NULL               |  550 | Using where |
# |    2 | DEPENDENT SUBQUERY | b          | ref   | tab_delete_c1 | tab_delete_c1 | 4       | test.tab_delete.c1 |   73 | Using index |
# +------+--------------------+------------+-------+---------------+---------------+---------+--------------------+------+-------------+
delete from view_delete where (select count(*) from tab_delete b where b.c1=view_delete.c1) = 500 limit 1;
affected rows: 1
delete from view_delete where (select count(*) from tab_delete b where b.c1=view_delete.c1) = 500 limit 1;
affected rows: 0
select count(*) from view_delete where c1=0;
count(*)
499
rollback;
#
# Delete throw a view (ALL access)
#
start transaction;
# Acces by pointer, initied = RND
# +------+--------------------+------------+------+---------------+---------------+---------+--------------------+------+-------------+
# | id   | select_type        | table      | type | possible_keys | key           | key_len | ref                | rows | Extra       |
# +------+--------------------+------------+------+---------------+---------------+---------+--------------------+------+-------------+
# |    1 | PRIMARY            | tab_delete | ALL  | tab_delete_c1 | NULL          | NULL    | NULL               |  589 | Using where |
# |    2 | DEPENDENT SUBQUERY | b          | ref  | tab_delete_c1 | tab_delete_c1 | 4       | test.tab_delete.c1 |  295 | Using index |
# +------+--------------------+------------+------+---------------+---------------+---------+--------------------+------+-------------+
delete from view_delete where (select count(*) from tab_delete b where b.c1=view_delete.c1) = 500 ;
affected rows: 500
select count(*) from view_delete where c1=0;
count(*)
0
rollback;
#
# Delete failed due to trigger
#
start transaction;
delete from tab_delete where c1=1 and (select count(*) from tab_delete b where b.c1=tab_delete.c1) > 0 order by c2 asc limit 10;
ERROR 45000: Unhandled user-defined exception condition
rollback;
start transaction;
delete from tab_delete where (select count(*) from tab_delete b where b.c1=tab_delete.c1) > 0 order by c1 desc limit 100;
ERROR 45000: Unhandled user-defined exception condition
select c1,count(*) from tab_delete group by c1;
c1	count(*)
0	500
1	50
2	20
3	20
rollback;
#
# Delete throw a view with returning
#
start transaction;
delete from tab_delete where (select count(*) from tab_delete b where b.c1=tab_delete.c1) = 500 order by c2 asc limit 10 returning c1,c2;
c1	c2
0	1
0	2
0	3
0	4
0	5
0	6
0	7
0	8
0	9
0	10
rollback;
start transaction;
delete from tab_delete where (select count(*) from tab_delete b where b.c1=tab_delete.c1) = 500 order by c2 desc limit 10 returning c1,c2;
c1	c2
0	491
0	492
0	493
0	494
0	495
0	496
0	497
0	498
0	499
0	500
rollback;
#
# Delete from table with more than 150000 rows
#
insert into tab_delete select * from tab_delete;
insert into tab_delete select * from tab_delete;
insert into tab_delete select * from tab_delete;
insert into tab_delete select * from tab_delete;
insert into tab_delete select * from tab_delete;
insert into tab_delete select * from tab_delete;
insert into tab_delete select * from tab_delete;
insert into tab_delete select * from tab_delete;
select count(*) from tab_delete;
count(*)
151040
with high memory for sort_buffer_size
SET SESSION sort_buffer_size = 1024000;
start transaction;
delete from tab_delete where c1=0 and exists(select 'x' from tab_delete b where b.c1<10);
affected rows: 128000
rollback;
with few memory for sort_buffer_size
SET SESSION sort_buffer_size = 1024;
start transaction;
delete from tab_delete where c1=0 and exists(select 'x' from tab_delete b where b.c1<10);
affected rows: 128000
rollback;
drop procedure if exists gendata;
drop view if exists view_delete;
drop table if exists tab_delete;