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Fixed mdev-14879 Lost rows for query using recursive CTE

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with recursive reference in subquery

If a recursive CTE uses a subquery with recursive reference then
the virtual function reset() must be called after each iteration
performed at the execution of the CTE.
This commit is contained in:
Igor Babaev 2018-01-06 09:32:47 -08:00
parent 075f61a1d4
commit 7d201d7b30
3 changed files with 132 additions and 0 deletions
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78
mysql-test/r/cte_recursive.result
View file

@ -2972,3 +2972,81 @@ WHERE 1 = 1
) K, t3;
C P i
drop table t1,t2,t3;
#
# mdev-14879: subquery with recursive reference in WHERE of CTE
#
create table flights
(departure varchar(32),
arrival varchar(32),
carrier varchar(20),
flight_number char(7));
insert into flights values
('Seattle', 'Frankfurt', 'Lufthansa', 'LH 491'),
('Seattle', 'Chicago', 'American', 'AA 2573'),
('Seattle', 'Los Angeles', 'Alaska Air', 'AS 410'),
('Chicago', 'New York', 'American', 'AA 375'),
('Chicago', 'Montreal', 'Air Canada', 'AC 3053'),
('Los Angeles', 'New York', 'Delta', 'DL 1197'),
('Moscow', 'Tokyo', 'Aeroflot', 'SU 264'),
('New York', 'Paris', 'Air France', 'AF 23'),
('Frankfurt', 'Moscow', 'Lufthansa', 'LH 1444'),
('Tokyo', 'Seattle', 'ANA', 'NH 178'),
('Los Angeles', 'Tokyo', 'ANA', 'NH 175'),
('Moscow', 'Los Angeles', 'Aeroflot', 'SU 106'),
('Montreal', 'Paris', 'Air Canada', 'AC 870'),
('Cairo', 'Paris', 'Air France', 'AF 503'),
('New York', 'Seattle', 'American', 'AA 45'),
('Paris', 'Chicago', 'Air France', 'AF 6734');
with recursive destinations (city) as
( select a.arrival from flights a where a.departure='Cairo'
union
select b.arrival from destinations r, flights b where r.city=b.departure)
select * from destinations;
city
Paris
Chicago
New York
Montreal
Seattle
Frankfurt
Los Angeles
Moscow
Tokyo
set standard_compliant_cte=0;
with recursive destinations (city, legs) as
(
select a.arrival, 1 from flights a where a.departure='Cairo'
union
select b.arrival, r.legs + 1 from destinations r, flights b
where r.city=b.departure and b.arrival not in (select city from destinations)
)
select * from destinations;
city legs
Paris 1
Chicago 2
New York 3
Montreal 3
Seattle 4
Frankfurt 5
Los Angeles 5
Moscow 6
Tokyo 6
explain extended with recursive destinations (city, legs) as
(
select a.arrival, 1 from flights a where a.departure='Cairo'
union
select b.arrival, r.legs + 1 from destinations r, flights b
where r.city=b.departure and b.arrival not in (select city from destinations)
)
select * from destinations;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 16 100.00
2 DERIVED a ALL NULL NULL NULL NULL 16 100.00 Using where
3 RECURSIVE UNION b ALL NULL NULL NULL NULL 16 100.00 Using where
3 RECURSIVE UNION <derived2> ref key0 key0 35 test.b.departure 2 100.00
4 DEPENDENT SUBQUERY <derived2> ALL NULL NULL NULL NULL 16 100.00 Using where
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL NULL
Warnings:
Note 1003 with recursive destinations as (select `test`.`a`.`arrival` AS `city`,1 AS `legs` from `test`.`flights` `a` where `test`.`a`.`departure` = 'Cairo' union select `test`.`b`.`arrival` AS `arrival`,`r`.`legs` + 1 AS `r.legs + 1` from `destinations` `r` join `test`.`flights` `b` where `r`.`city` = `test`.`b`.`departure` and !<in_optimizer>(`test`.`b`.`arrival`,<exists>(select `destinations`.`city` from `destinations` where trigcond(`test`.`b`.`arrival` = `destinations`.`city` or `destinations`.`city` is null) having trigcond(`destinations`.`city` is null))))select `destinations`.`city` AS `city`,`destinations`.`legs` AS `legs` from `destinations`
set standard_compliant_cte=default;
drop table flights;

53
mysql-test/t/cte_recursive.test
View file

@ -2032,3 +2032,56 @@ FROM
) K, t3;
drop table t1,t2,t3;
--echo #
--echo # mdev-14879: subquery with recursive reference in WHERE of CTE
--echo #
create table flights
(departure varchar(32),
arrival varchar(32),
carrier varchar(20),
flight_number char(7));
insert into flights values
('Seattle', 'Frankfurt', 'Lufthansa', 'LH 491'),
('Seattle', 'Chicago', 'American', 'AA 2573'),
('Seattle', 'Los Angeles', 'Alaska Air', 'AS 410'),
('Chicago', 'New York', 'American', 'AA 375'),
('Chicago', 'Montreal', 'Air Canada', 'AC 3053'),
('Los Angeles', 'New York', 'Delta', 'DL 1197'),
('Moscow', 'Tokyo', 'Aeroflot', 'SU 264'),
('New York', 'Paris', 'Air France', 'AF 23'),
('Frankfurt', 'Moscow', 'Lufthansa', 'LH 1444'),
('Tokyo', 'Seattle', 'ANA', 'NH 178'),
('Los Angeles', 'Tokyo', 'ANA', 'NH 175'),
('Moscow', 'Los Angeles', 'Aeroflot', 'SU 106'),
('Montreal', 'Paris', 'Air Canada', 'AC 870'),
('Cairo', 'Paris', 'Air France', 'AF 503'),
('New York', 'Seattle', 'American', 'AA 45'),
('Paris', 'Chicago', 'Air France', 'AF 6734');
with recursive destinations (city) as
( select a.arrival from flights a where a.departure='Cairo'
union
select b.arrival from destinations r, flights b where r.city=b.departure)
select * from destinations;
set standard_compliant_cte=0;
let $q=
with recursive destinations (city, legs) as
(
select a.arrival, 1 from flights a where a.departure='Cairo'
union
select b.arrival, r.legs + 1 from destinations r, flights b
where r.city=b.departure and b.arrival not in (select city from destinations)
)
select * from destinations;
eval $q;
eval explain extended $q;
set standard_compliant_cte=default;
drop table flights;

1
sql/sql_union.cc
View file

@ -1284,6 +1284,7 @@ bool st_select_lex_unit::exec_recursive()
sq;
sq= sq->next_with_rec_ref)
{
sq->reset();
sq->engine->force_reexecution();
}