Postgres：准备好的声明已经存在

我在我的Rails API应用程序中使用Devise进行身份validation。 有时我在日志中看到以下错误：

ActiveRecord :: StatementInvalid：PGError：错误：准备好的语句“a3926”已经存在：UPDATE“users”SET“current_sign_in_at”= $ 1，“last_sign_in_at”= $ 2，“sign_in_count”= $ 3，“updated_at”= $ 4 WHERE“users”。 “id”= 12345

错误来自Devise：

def update_tracked_fields!(request) old_current, new_current = self.current_sign_in_at, Time.now.utc self.last_sign_in_at = old_current || new_current self.current_sign_in_at = new_current old_current, new_current = self.current_sign_in_ip, request.remote_ip self.last_sign_in_ip = old_current || new_current self.current_sign_in_ip = new_current self.sign_in_count ||= 0 self.sign_in_count += 1 # error happens below save(validate: false) or raise "Devise trackable could not save #{inspect}." \ "Please make sure a model using trackable can be saved at sign in." end 

据我所知，当数据库连接的使用方式出现问题时，通常会发生此错误。 有什么我应该找的吗？

Answer 1

如果您正在使用一个提供进程的服务器（如独角兽），则需要为每个分叉进程创建一个连接。

如果是独角兽，请添加：

 #config/unicorn.rb before_fork do |server, worker| Signal.trap 'TERM' do puts 'Unicorn master intercepting TERM and sending myself QUIT instead' Process.kill 'QUIT', Process.pid end defined?(ActiveRecord::Base) and ActiveRecord::Base.connection.disconnect! end after_fork do |server, worker| Signal.trap 'TERM' do puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to sent QUIT' end defined?(ActiveRecord::Base) and ActiveRecord::Base.establish_connection( Rails.application.config.database_configuration[Rails.env] ) end