我想使用的计算,是一个d距离从一个点(即地理位置的东西)远点的查询,所以查询有些复杂:django查询和存储过程(MySQL)之间的性能差异?
DELIMITER //
CREATE PROCEDURE geodist (IN m_lat double, IN m_lng double, IN dist int, IN lim int)
BEGIN
DECLARE lon1 double; DECLARE lon2 double;
DECLARE lat1 double; DECLARE lat2 double;
-- calculate lon lat for the rectangle
SET lon1 = m_lon-dist/abs(cos(radians(m_lat))*69);
SET lon2 = m_lon+dist/abs(cos(radians(m_lat))*69);
SET lat1 = m_lat-(dist/69);
SET lat2 = m_lat+(dist/69);
-- run query;
SELECT post.id, 3956 * 2 * ASIN(SQRT(POWER(SIN((m_lat - post.geo_lat) * pi()/180/2), 2) +COS(m_lat * pi()/180) * COS(post.geo_lat * pi()/180) *POWER(SIN((m_lng - post.geo_lng) * pi()/180/2), 2))) as distance
FROM post_post as post
WHERE
post.geo_lng BETWEEN lon1 AND lon2
AND post.geo_lat BETWEEN lat1 AND lat2
HAVING distance < dist ORDER BY Distance limit lim;
END //
远高于正是我的存储过程会。由于我将使用这个来通过数千甚至数百万行数据,我想知道在存储过程中使用django查询时性能会怎样?我意识到,Django不支持存储过程,所以这就是为什么我希望避免使用存储过程。然而,那么查询将不会被编译到数据库中,并且计算将不得不在python中完成......等等。django查询和从django调用的存储过程之间的性能有什么区别?
你问了这个问题3次。这是一个交叉点。 – Bytemain 2012-01-10 02:04:16