在 Rails / ActiveRecord 中命名 SQL 查询

Question

将 Rails 与 ActiveRecord（和 PostgreSQL）一起使用时，执行“简单”查询会为它们添加一个名称，例如调用

Article.all
# => Article Load (2.6ms)  SELECT "articles".* FROM "articles"

命名查询Article Load。但是，当执行稍微复杂的查询时，不会生成名称，例如

Article.group(:article_group_id).count
# => (1.2ms)  SELECT COUNT(*) AS count_all, "articles"."article_group_id" AS articles_article_group_id FROM "articles" GROUP BY "articles"."article_group_id"

如果使用以下execute方法执行自定义查询，我可以添加一个名称：

ActiveRecord::Base.connection.execute("SELECT * FROM articles", "My custom query name")
# => My custom query name (2.5ms)  SELECT * FROM articles

但是有没有办法将自定义名称添加到使用 ActiveRecord 方法构建的查询中？

如果您想知道为什么：该名称对于所有类型的监控都很有用，例如在 AppSignal 中查看慢查询时。

Answer 1

由于您只想自定义查询名称以进行监控，所以我认为您只需要更改方法query name中的ActiveRecord::ConnectionAdapters#log，该方法是记录要执行的 sql 查询的方法，包括query name.

这是我的解决方案：

# lib/active_record/base.rb
# note that MUST be base.rb
# otherwise you need to add initializer to extend Rails core
#
module ActiveRecord
  module ConnectionAdapters
    class AbstractAdapter
      attr_accessor :log_tag

      private

      alias old_log log
      def log(sql, name = "SQL", binds = [], type_casted_binds = [], statement_name = nil)
        if name != 'SCHEMA'
          name = @log_tag
          @log_tag = nil # reset
        end

        old_log(sql, name, binds, type_casted_binds, statement_name) do
          yield
        end
      end
    end
  end

  module QueryMethods
    def log_tag(tag_name) # class method
      spawn.log_tag(tag_name)
      self
    end
  end

  module Querying
    delegate :log_tag, to: :all
  end

  class Relation
    def log_tag(tag_name) # instance method
      conn = klass.connection
      conn.log_tag = tag_name
      self
    end
  end
end

演示

Task.log_tag("DEMO").group(:status).count
# DEMO (0.7ms)  SELECT COUNT(*) AS count_all, "tasks"."status" AS tasks_status FROM "tasks" GROUP BY "tasks"."status"

Task.where(status: 6).log_tag("SIX").first(20)
# SIX (0.8ms)  SELECT "tasks".* FROM "tasks" WHERE "tasks"."status" = ? ORDER BY "tasks"."id" ASC LIMIT ?

Task.where(status: 6).first(20)
# (0.8ms)  SELECT "tasks".* FROM "tasks" WHERE "tasks"."status" = ? ORDER BY "tasks"."id" ASC LIMIT ?

笔记

如果你想修复query name特定的查询，你可以使用一个散列，键是整个特定的sql字符串（或整个sql的散列，例如Rails核心缓存查询的方式：）query_signature = ActiveSupport::Digest.hexdigest(to_sql)，值是query name你想要的。

# set up before hand
ActiveRecord::ConnectionAdapters::LogTags[Product.where...to_sql] = "DEMO"
# AbstractAdapter
LogTags = Hash.new
def log(sql, name...)
  name = LogTags[sql]
  # ...
end