将 Rails 与 Oracle 结合使用时，为什么会出现“无侦听器”错误？答案

【问题标题】：Why do I get a "no listener" error when using Rails with Oracle?将 Rails 与 Oracle 结合使用时，为什么会出现“无侦听器”错误？
【发布时间】：2010-02-01 11:08:58
【问题描述】：

我使用 Rails 2.3.5 和 Oracle 10 作为我的数据库，使用 "oracle_adapter" 和 ruby-oci8 连接到 Oracle 主机。

我得到了这个例外：

在 463 毫秒内完成（查看：18，DB：166）| 200 OK [http://192.168.30.128/auctions?page=1] /!\ FAILSAFE /!\ 2010 年 2 月 1 日星期一 19:02:11 +0800 状态：500 内部服务器错误 ORA-12541: TNS: 没有监听器 env.c:257:in oci8lib.so /home/qichunren/.gem/ruby/1.8/gems/ruby-oci8-1.0.7/lib/oci8.rb:229:in `initialize' /home/qichunren/.gem/ruby/1.8/gems/activerecord-oracle-adapter-1.0.0.9250/lib/active_record/connection_adapters/oracle_adapter.rb:623:in `new' /home/qichunren/.gem/ruby/1.8/gems/activerecord-oracle-adapter-1.0.0.9250/lib/active_record/connection_adapters/oracle_adapter.rb:623:in `new_connection' /home/qichunren/.gem/ruby/1.8/gems/activerecord-oracle-adapter-1.0.0.9250/lib/active_record/connection_adapters/oracle_adapter.rb:659:in `initialize' /home/qichunren/.gem/ruby/1.8/gems/activerecord-oracle-adapter-1.0.0.9250/lib/active_record/connection_adapters/oracle_adapter.rb:35:in `new' /home/qichunren/.gem/ruby/1.8/gems/activerecord-oracle-adapter-1.0.0.9250/lib/active_record/connection_adapters/oracle_adapter.rb:35:in `oracle_connection' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in `send' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in `new_connection' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:245:in `checkout_new_connection' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:188:in `checkout' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in `loop' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in `checkout' /usr/local/ruby187/lib/ruby/1.8/monitor.rb:242:in `同步' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:183:in `checkout' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:98:in `connection' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:326:in `retrieve_connection' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_specification.rb:123:in `retrieve_connection' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_specification.rb:115:in `connection' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/query_cache.rb:9:in `cache' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/query_cache.rb:28:in `call' /home/qichunren/.gem/ruby/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:361:in `call' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/string_coercion.rb:25:in `call' /home/qichunren/.gem/ruby/1.8/gems/rack-1.0.1/lib/rack/head.rb:9:in `call' /home/qichunren/.gem/ruby/1.8/gems/rack-1.0.1/lib/rack/methodoverride.rb:24:in `call' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/params_parser.rb:15:in `call' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/session/cookie_store.rb:93:in `call' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/failsafe.rb:26:in `call' /home/qichunren/.gem/ruby/1.8/gems/rack-1.0.1/lib/rack/lock.rb:11:in `call' /home/qichunren/.gem/ruby/1.8/gems/rack-1.0.1/lib/rack/lock.rb:11:in `同步' /home/qichunren/.gem/ruby/1.8/gems/rack-1.0.1/lib/rack/lock.rb:11:in `call' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:114:in `call' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/reloader.rb:34:in `run' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:108:in `call' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/cgi_process.rb:44:in `dispatch_cgi' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:101:in `dispatch_cgi' /home/qichunren/.gem/ruby/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:27:in `dispatch' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:76:in `进程' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:74:in `同步' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:74:在“进程”中 /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:159:in `process_client' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:158:in `每个' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:158:in `process_client' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:285:in `run' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:285:in `initialize' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:285:in `new' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:285:in `run' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:268:in `initialize' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:268:in `new' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel.rb:268:in `run' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/configurator.rb:282:in `run' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/configurator.rb:281:in `each' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/configurator.rb:281:in `run' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/command.rb:212:in `run' /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281 /home/qichunren/.gem/ruby/1.8/bin/mongrel_rails:19:in `load' /home/qichunren/.gem/ruby/1.8/bin/mongrel_rails:19

与 Oracle 的连接似乎经常断开。它显示oracle error:**ORA-12541: TNS:no listener**。

我该如何解决这个问题？

oci8.c:270:in oci8lib.so: ORA-12541: TNS:no listener (OCIError) 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connection_adapters/oracle_enhanced_oci_connection.rb:223:in `new' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connection_adapters/oracle_enhanced_oci_connection.rb:223:in `new_connection' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connection_adapters/oracle_enhanced_oci_connection.rb:328:in `initialize' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connection_adapters/oracle_enhanced_oci_connection.rb:24:in `new' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connection_adapters/oracle_enhanced_oci_connection.rb:24:in `initialize' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connection_adapters/oracle_enhanced_connection.rb:9:in `new' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connection_adapters/oracle_enhanced_connection.rb:9:in `create' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connection_adapters/oracle_enhanced_adapter.rb:50:in `oracle_enhanced_connection' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/connection_adapters/abstract/c onnection_specification.rb:291:in `send' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/connection_adapters/abstract/c onnection_specification.rb:291:in `connection=' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/connection_adapters/abstract/c onnection_specification.rb:259:in `retrieve_connection' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/connection_adapters/abstract/c onnection_specification.rb:78:in 'connection' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/base.rb:2438:in `quoted_table_name' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/base.rb:1259:in `find_one' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/base.rb:1250:in `find_from_ids' 来自 /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/base.rb:504:in `find' 来自脚本/维护/adjust_settlement.rb:19

【问题讨论】：

标签： ruby-on-rails ruby oracle ora-12541

【解决方案1】：

首先您应该使用oracle_enhanced adapter，因为不再支持原始的oracle 适配器。我还建议使用最新的ruby-oci8 version 2.0.3。还要检查您使用的是哪个 Oracle 客户端版本 - 我推荐 Oracle Instant Client 10.2.0.4 或更高版本

但是，如果您收到 ORA-12541: TNS:no listener 错误，那么问题可能出在与数据库的网络连接或 Oracle 服务器端的某些问题上。但是请尝试 oracle_enhanced 适配器和最新的 ruby-oci8 版本，看看它是否能解决您的问题。

【讨论】：

er，事实上，我正在使用测试 ruby-oci8 2 和 1，以及 oracle 和 oracle-enhanced 适配器。 oracle instantclient 11_2 我在生产模式下发现的，我几乎没有收到这个错误，但在开发模式下，经常收到没有监听器错误，500响应代码

【解决方案2】：

确保：

您在 ${ORACLE_HOME}/network/admin/tnsnames.ora 中正确设置了连接名称。
您在加载 oci8 驱动程序之前设置了 ORACLE_HOME。

如果这不起作用，请明确指定 host[:port]/sid 作为数据库名称。

例如如果你的主机是 mydbhost.myorg.org，端口号是 1522，sid 是employeedb，你会使用这个：

数据库：mydbhost.myorg.org:1522/employeedb

如果你的端口是默认的1521，你可以省略冒号和端口号。

【讨论】：

【解决方案3】：

我认为您的听众由于没有活动而超时。我怀疑您正在打开连接，发出查询，然后在代码空闲等待另一个客户端请求时使连接保持打开状态。如果您的数据库设置为允许永久连接，但这样会耗尽所有池，这是大多数网站不希望的。

您可以调整数据库以允许更长的会话，或者告诉它根本不断开连接，或者修改您的代码以在尝试发送查询之前检查连接，如有必要重新连接，然后继续。

并非所有数据库适配器都允许您进行保持活动/检测信号甚至询问服务器连接是否处于活动状态，因此我不得不恢复为在异常处理程序中从表中包装一个简单的select 1，只是在继续之前戳连接。

另一种选择是将一个简单的“保持活动”例程放在一个单独的线程中，该线程定期执行一个简单的请求，例如select 1，以保持数据库运行良好。如果该例程检测到连接已断开，则它将负责将“db_connection_up”标志设置为false 或重新连接。

您必须根据要处理的请求数量来确定处理它的最佳方式。连接、发出一个微小的请求，然后反复断开连接，是一种不同的坏事，所以你必须找到一个快乐的媒介。

与您的 DBA 交谈，了解 Oracle DB 中的超时时间，以及是否可以更改或是否可以获得永久连接。如果没有，请调整您的代码。

在 google 上搜索“oracle listener timeout”以获取更多信息。

【讨论】：

【解决方案4】：

Kelvin 的回答对我有用。此外，还有另一种方法。

我使用的是 rails 4.1.x，Gemfile：

gem 'activerecord-oracle_enhanced-adapter', '~> 1.5.0'
gem 'ruby-oci8', '2.2.3'

数据库.yml：

# not work!
host:  218.5.173.xxx/my_db

# works, solution 1:  
database: 218.5.173.xxx/my_db


# works, solution 2: 
database: "(DESCRIPTION=
(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=218.5.173.xxx)(PORT=1521)))
(CONNECT_DATA=(SERVICE_NAME=my_db))
)"

【讨论】：