ruby-on-rails - Rails with PostgreSQL 每个请求重新连接多次

Question

我最近遇到一个问题，Rails 正在断开与我的 PostgreSQL 的连接，导致每个请求多次重新连接，从而显着减慢请求速度。我目前使用以下环境在 Mac OS X 上本地运行所有内容:

• Mac OS X 10.8(山狮)
• 战俘
• NginX(ssl 展开 - 相同的应用程序重新连接行为，即使没有启用此功能)
• 通过 Homebrew 的 PostgreSQL 9.2.2
• rails 3.2.11

这是我的 database.yml : (已编辑数据库和用户名)

development:
  adapter: postgresql
  encoding: unicode
  database: <database>
  pool: 5
  username: <user>
  password:

这是 development.log 的输出在一个典型的请求期间:(特定模型和渲染编辑)

Connecting to database specified by database.yml


Started GET "/" for 127.0.0.1 at 2013-02-05 12:25:38 -0800
Processing by HomeController#index as HTML
  ... <app performs model loads and render calls>
Completed 200 OK in 314ms (Views: 196.0ms | ActiveRecord: 60.9ms)
Connecting to database specified by database.yml
Connecting to database specified by database.yml

我还在 Postgres 中启用了语句日志记录，以便更好地了解在给定请求期间数据库端到底发生了什么。这是 postgresql-<date>.log 的输出: (已编辑特定于我的应用的查询)

LOG:  connection received: host=[local]
LOG:  connection authorized: user=<user> database=<database>
LOG:  statement: set client_encoding to 'UTF8'
LOG:  statement: set client_encoding to 'unicode'
LOG:  statement: SHOW client_min_messages
LOG:  statement: SET client_min_messages TO 'panic'
LOG:  statement: SET standard_conforming_strings = on
LOG:  statement: SET client_min_messages TO 'notice'
LOG:  statement: SET time zone 'UTC'
LOG:  statement: SHOW TIME ZONE
LOG:  statement: SELECT 1
LOG:  statement: SELECT 1
    ... <app makes queries for request>
LOG:  disconnection: session time: 0:00:01.346 user=<user> database=<database> host=[local]
LOG:  connection received: host=[local]
LOG:  connection authorized: user=<user> database=<database>
LOG:  statement: set client_encoding to 'UTF8'
LOG:  statement: set client_encoding to 'unicode'
LOG:  statement: SHOW client_min_messages
LOG:  statement: SET client_min_messages TO 'panic'
LOG:  statement: SET standard_conforming_strings = on
LOG:  statement: SET client_min_messages TO 'notice'
LOG:  statement: SET time zone 'UTC'
LOG:  statement: SHOW TIME ZONE
LOG:  statement: SELECT 1
LOG:  connection received: host=[local]
LOG:  connection authorized: user=<user> database=<database>
LOG:  statement: set client_encoding to 'UTF8'
LOG:  statement: set client_encoding to 'unicode'
LOG:  statement: SHOW client_min_messages
LOG:  statement: SET client_min_messages TO 'panic'
LOG:  statement: SET standard_conforming_strings = on
LOG:  statement: SET client_min_messages TO 'notice'
LOG:  statement: SET time zone 'UTC'
LOG:  statement: SHOW TIME ZONE
LOG:  statement: SELECT 1
LOG:  statement: SELECT 1
LOG:  statement: SELECT 1
LOG:  disconnection: session time: 0:00:00.750 user=<user> database=<database> host=[local]
LOG:  disconnection: session time: 0:00:00.733 user=<user> database=<database> host=[local]

我很乐意为命令调用更新相关配置或日志输出。另外，为什么所有 SELECT 1电话？他们的目的是什么？

谢谢!

Answer 1

答案是将 PostgreSQL 升级到更新的版本。我刚刚升级到 9.2.4来自 9.2.2正如在原始问题中使用的那样，问题完全消失了，我的开发应用程序恢复了预期的性能特征。