Question

I got this query. It take ~0.0854 seconds to excutes. I find it a little slow. Below see my explain

SELECT
    stops.stop_number,
    stops.stop_name_1,
    stops.stop_name_2
FROM
    tranzit.stops_times

INNER JOIN 
    tranzit.stops
ON
    (
        stops_times.stop_id = stops.stop_id
    )

INNER JOIN 
    tranzit.trips
ON
    (
        stops_times.trip_id = trips.trip_id
    )   
WHERE
    trips.route_id = 109 AND
    trips.trip_direction = 1 AND
    trips.trip_period_start <= "2011-11-24" AND
    trips.trip_period_end >= "2011-11-24"

GROUP BY
    stops.stop_id
ORDER BY
    stops_times.time_sequence ASC
LIMIT 
    0, 200

Explain

id  select_type     table           type            possible_keys                                           key                         key_len     ref                             rows    Extra
1   SIMPLE          trips           index_merge     trip_id,trip_period_start,trip_period_end,trip_dir...   route_id,trip_direction     3,1         NULL                            271     Using intersect(route_id,trip_direction); Using wh...
1   SIMPLE          stops_times     ref             stop_id,trip_id                                         trip_id                     16          tranzit.trips.trip_id           24   
1   SIMPLE          stops           ref             stop_id                                                 stop_id                     3           tranzit.stops_times.stop_id     1       Using where

And I have indexe on trips :

Table   Non_unique  Key_name    Seq_in_index    Column_name     Collation   Cardinality     Sub_part    Packed  Null    Index_type  Comment
trips   1   agency_id   1   agency_id   A   2   NULL    NULL        BTREE    
trips   1   trip_id     1   trip_id     A   9361    NULL    NULL        BTREE    
trips   1   trip_period_start   1   trip_period_start   A   2   NULL    NULL        BTREE    
trips   1   trip_period_end     1   trip_period_end     A   2   NULL    NULL        BTREE    
trips   1   trip_direction  1   trip_direction  A   2   NULL    NULL        BTREE    
trips   1   route_id    1   route_id    A   106     NULL    NULL        BTREE    
trips   1   shape_id    1   shape_id    A   520     NULL    NULL        BTREE    
trips   1   trip_terminus   1   trip_terminus   A   301     NULL    NULL        BTREE    

Indexes on stops

stop_number BTREE   Non Non stop_number 4626    A       
agency_id   BTREE   Non Non agency_id   1   A       
stop_id BTREE   Non Non stop_id 4626    A       

Thanks for any help

Answer 1

I found something that work like a charm. My results number are :

• 0.0011
• 0.0008
• 0.0017 (highest)
• 0.0006 (lowest)
• 0.0013

These result aren’t from the cache. I switch all the WHERE in t (trips.agency_id, trips.route_id, trips.trip_direction, trips.trip_period_start, trips.trip_period_end) and it is working very good ! I can’t explain why but if someone can, i’d like to see why. Thanks a lot everyone !

PS : Even without trips.agency_id it is working great.

SELECT
    stops.stop_number, 
    stops.stop_name_1, 
    stops.stop_name_2
FROM 
    tranzit.stops_times,
    tranzit.stops,
    (
        SELECT 
            trips.trip_id
        FROM
            tranzit.trips
        WHERE
            trips.agency_id = 5 AND
            trips.route_id = 109 AND
            trips.trip_direction = 0 AND
            trips.trip_period_start <= "2011-12-01" AND
            trips.trip_period_end >= "2011-12-01"
        LIMIT 1
    ) as t

WHERE 
    stops_times.stop_id = stops.stop_id AND
    stops_times.trip_id in (t.trip_id)
GROUP BY
    stops_times.stop_id
ORDER BY
    stops_times.time_sequence ASC
LIMIT 
    0, 200


id  select_type     table           type        possible_keys       key         key_len     ref                             rows    Extra
1   PRIMARY         <derived2>      system      NULL                NULL        NULL        NULL                            1       Using temporary; Using filesort
1   PRIMARY         stops_times     ref         trip_id,stop_id     trip_id     16          const                           33      Using where
1   PRIMARY         stops           ref         stop_id             stop_id     3           tranzit.stops_times.stop_id     1       Using where
2   DERIVED         trips           ref         testing             testing     4                                           275     Using where