Question

我很擅长优化我的查询，我有一个N + 1查询，它似乎需要一个计数器，但我不确定如何继续：

...
SQL (0.5ms)  SELECT COUNT(*) AS count_id FROM (SELECT 1 FROM `photos` WHERE (`photos`.attachable_id = 4864 AND `photos`.attachable_type = 'Recipe')) AS subquery
SQL (2.1ms)  SELECT COUNT(*) AS count_id FROM (SELECT 1 FROM `votes` WHERE (`votes`.voteable_id = 4864 AND `votes`.voteable_type = 'Recipe') AND (`votes`.`vote` = 1)) AS subquery
SQL (2.0ms)  SELECT COUNT(*) AS count_id FROM (SELECT 1 FROM `votes` WHERE (`votes`.voteable_id = 4864 AND `votes`.voteable_type = 'Recipe') AND (`votes`.`vote` = 0)) AS subquery
SQL (0.3ms)  SELECT COUNT(*) AS count_id FROM (SELECT 1 FROM `photos` WHERE (`photos`.attachable_id = 4865 AND `photos`.attachable_type = 'Recipe')) AS subquery
SQL (2.6ms)  SELECT COUNT(*) AS count_id FROM (SELECT 1 FROM `votes` WHERE (`votes`.voteable_id = 4865 AND `votes`.voteable_type = 'Recipe') AND (`votes`.`vote` = 1)) AS subquery
SQL (2.4ms)  SELECT COUNT(*) AS count_id FROM (SELECT 1 FROM `votes` WHERE (`votes`.voteable_id = 4865 AND `votes`.voteable_type = 'Recipe') AND (`votes`.`vote` = 0)) AS subquery
...

所以我有两件奇怪的事情在这里造成问题。我有这种多态vote模型，我需要对它们进行总结，基本上如果有人投了一票，它在0列上的值为vote，并且{ {1}}如果用户投了票。但是看起来它会创建这个疯狂的查询。

我该如何解决这个问题？

我认为造成这种情况的事情在我看来是以这种方法开始的：

这就是我统计选票的方式：

<%= recipe.votes.tally %>

但是因为我正在为每个对象做这件事，所以我必须多次执行这个逻辑，我们最终会得到一个疯狂的N + 1.

Answer 1

当你写作时，

我认为造成这种情况的事情在我看来是以这种方法开始的：

＆LT; ％= recipe.votes.tally％＆gt;

通过在脚本/控制台中获取配方实例，您可以找到更多确定性并执行 recipe.votes.tally 那里

不太确定，这有点模糊，但您是否可以考虑将您的计数方法放在食谱模型中？ - 斯蒂芬

修复需要计数器的Rails中的N + 1个查询

1 个答案: