我使用rails 4.2.5。 我在这段代码中遇到了某种N + 1问题
seats=SeatItem.where(:b => hall.id).all
seats.each do |seat|
arr << Ticket.new(:a => seat.id)
end
Ticket.import arr
这段代码的问题是我在日志中有这个
MIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE "seat_item_types"."id" = $1 LIMIT 1 [["id", 13]]
CACHE (0.0ms) SELECT "seat_item_types".* FROM "seat_item_types" WHERE
为什么:all方法不会在内存中加载所有内容以及如何修复它？
感谢您的投入！
答案 0 :(得分：0)
您应该使用eager_load来解决N + 1查询问题
使用包括这样的方法
IEnumerable<IGrouping<string,object>>http://guides.rubyonrails.org/active_record_querying.html#eager-loading-associations
但首先，我认为您在SeatItem和Ticket上定义关联 http://guides.rubyonrails.org/association_basics.html
答案 1 :(得分：0)
我认为var myapp = angular.module("myapp", []);
myapp.controller("MyController", *function($scope, $interval)*{
$interval(callAtInterval, 5000);
});
function callAtInterval() {
console.log("Interval occurred");
}
不是问题所在。请注意，重复的SQL查询是相同的，并且它从:all而不是seat_item_types获取行。我的猜测是你有一个前/后钩子或其他一些由seat_items或Ticket.new触发Ticket.import的代码。