Hmm, weird. I just re-imported the data (after drop/create table, etc.), and
now the spatial queries run fast.
Has anyone seen this sort of thing happen? Maybe the Index got corrupted
somehow, and then MySQL had to do a full table scan (even though EXPLAIN
indicated it would use the Spatial Index)?
On 2009-12-28, at 9:28 AM, René Fournier wrote:
> So just to clarify (hello?), the index which *should* be used (EXPLAIN says
> so) and *should* make the query run faster than 4 seconds either isn't used
> (why?) or simply doesn't speed up the query (again, why?).
>
> +----+-------------+-------+-------+---------------+-------+---------+------+------+-------------+
> | id | select_type | table | type | possible_keys | key | key_len | ref |
> rows | Extra |
> +----+-------------+-------+-------+---------------+-------+---------+------+------+-------------+
> | 1 | SIMPLE | qs | range | coord | coord | 27 | NULL |
> 5260 | Using where |
> +----+-------------+-------+-------+---------------+-------+---------+------+------+-------------+
>
> SELECT id, province, latitude, longitude, AsText(coordinates), s_ts_r_m,
> quartersection FROM qs WHERE MBRContains(GeomFromText('POLYGON((51.62582589
> -114.82248918,51.65126254 -114.82248918,51.65126254 -114.78150333,51.62582589
> -114.78150333,51.62582589 -114.82248918))'), coordinates)
>
> 8 rows in set (3.87 sec)
>
>
> On 2009-12-27, at 3:59 PM, René Fournier wrote:
>
>> So... there is an index, and it's supposedly used:
>>
>> mysql> EXPLAIN SELECT id, province, latitude, longitude,
>> AsText(coordinates), s_ts_r_m, quartersection FROM qs WHERE
>> MBRContains(GeomFromText('POLYGON((51.62582589 -114.82248918,51.65126254
>> -114.82248918,51.65126254 -114.78150333,51.62582589
>> -114.78150333,51.62582589 -114.82248918))'), coordinates);
>> +----+-------------+-------+-------+---------------+-------+---------+------+------+-------------+
>> | id | select_type | table | type | possible_keys | key | key_len | ref
>> | rows | Extra |
>> +----+-------------+-------+-------+---------------+-------+---------+------+------+-------------+
>> | 1 | SIMPLE | qs | range | coord | coord | 27 | NULL
>> | 5260 | Using where |
>> +----+-------------+-------+-------+---------------+-------+---------+------+------+-------------+
>> 1 row in set (0.00 sec)
>>
>> But when I run the query:
>>
>> mysql> SELECT id, province, latitude, longitude, AsText(coordinates),
>> s_ts_r_m, quartersection FROM qs WHERE
>> MBRContains(GeomFromText('POLYGON((51.62582589 -114.82248918,51.65126254
>> -114.82248918,51.65126254 -114.78150333,51.62582589
>> -114.78150333,51.62582589 -114.82248918))'), coordinates)
>> -> ;
>> +--------+----------+-------------+---------------+----------------------------------+--------------+----------------+
>> | id | province | latitude | longitude | AsText(coordinates)
>> | s_ts_r_m | quartersection |
>> +--------+----------+-------------+---------------+----------------------------------+--------------+----------------+
>> | 444543 | AB | 51.63495228 | -114.79282412 | POINT(51.63495228
>> -114.79282412) | 04-031-06 W5 | N4 |
>> | 444564 | AB | 51.64941120 | -114.79283278 | POINT(51.6494112
>> -114.79283278) | 09-031-06 W5 | N4 |
>> | 444548 | AB | 51.63497789 | -114.81645649 | POINT(51.63497789
>> -114.81645649) | 05-031-06 W5 | N4 |
>> | 444561 | AB | 51.64943119 | -114.81643801 | POINT(51.64943119
>> -114.81643801) | 08-031-06 W5 | N4 |
>> | 444547 | AB | 51.62775680 | -114.80475858 | POINT(51.6277568
>> -114.80475858) | 05-031-06 W5 | E4 |
>> | 444549 | AB | 51.63498028 | -114.80479925 | POINT(51.63498028
>> -114.80479925) | 05-031-06 W5 | NE |
>> | 444560 | AB | 51.64220442 | -114.80478262 | POINT(51.64220442
>> -114.80478262) | 08-031-06 W5 | E4 |
>> | 444562 | AB | 51.64942854 | -114.80476596 | POINT(51.64942854
>> -114.80476596) | 08-031-06 W5 | NE |
>> +--------+----------+-------------+---------------+----------------------------------+--------------+----------------+
>> 8 rows in set (3.87 sec)
>>
>> So, there are ~2.6 million rows in the table, and coordinates is
>> spatially-indexed. Yet the query requires nearly 4 seconds. What am I doing
>> wrong?
>>
>> ...REne
>
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