Php 优化/替换此自引用更新查询
我有此更新查询:Php 优化/替换此自引用更新查询,php,mysql,sql,optimization,Php,Mysql,Sql,Optimization,我有此更新查询: UPDATE aggregate_usage_input t JOIN (SELECT t2.id FROM aggregate_usage_input t2 WHERE t2.is_excluded_total_gallons = 0 AND t2.is_excluded_cohort = 0 AND t2.is_e
UPDATE aggregate_usage_input t
JOIN (SELECT t2.id
FROM aggregate_usage_input t2
WHERE t2.is_excluded_total_gallons = 0
AND t2.is_excluded_cohort = 0
AND t2.is_excluded_outlier = 0
ORDER BY t2.occupant_bucket_id,
t2.residence_type_bucket_id,
t2.reading_year,
t2.nthreading,
t2.total_gallons)t_sorted
ON t_sorted.id = t.id
SET t.rownum = @rownum := @rownum + 1
它根据排序更新rownum字段(实际上是orderby字段)
select查询需要9秒钟,因为我们使用order by,所以它是可以接受的
此查询的更新部分需要很长时间。在400.000记录表上记录超过5分钟。我们需要把它缩短到一分钟左右
如何加快速度,或者您是否有其他方法来解决此问题?子查询将在此处减慢您的速度。在实践中,我注意到将子查询分离成临时表或表变量更快 尝试:
你不明白我的问题。ORDERBY是这个查询的本质,这就是我们这样做的原因。
CREATE TEMPORARY TABLE Temp (id int);
INSERT INTO Temp
SELECT t2.id
FROM aggregate_usage_input t2
WHERE t2.is_excluded_total_gallons = 0
AND t2.is_excluded_cohort = 0
AND t2.is_excluded_outlier = 0
ORDER BY t2.occupant_bucket_id,
t2.residence_type_bucket_id,
t2.reading_year,
t2.nthreading,
t2.total_gallons;
UPDATE aggregate_usage_input t
JOIN Temp t_sorted
ON t_sorted.id = t.id
SET t.rownum = @rownum := @rownum + 1