爲什麼使用Rails和Oracle時會出現「無監聽者」錯誤？

Question

我正在使用Rails 2.3.5和Oracle 10作爲我的數據庫，使用「oracle_adapter」和ruby-oci8連接到Oracle主機。

我得到這個異常：

 
Completed in 463ms (View: 18, DB: 166) | 200 OK [http://192.168.30.128/auctions?page=1] 
/!\ FAILSAFE /!\ Mon Feb 01 19:02:11 +0800 2010 
    Status: 500 Internal Server Error 
    ORA-12541: TNS:no listener 
    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 `synchronize' 
    /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 `synchronize' 
    /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 `process' 
    /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:74:in `synchronize' 
    /home/qichunren/.gem/ruby/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:74:in `process' 
    /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 `each' 
    /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 

似乎和Oracle的連接經常掉線。它顯示oracle error:**ORA-12541: TNS:no listener**。

我該如何解決這個問題？

 
oci8.c:270:in oci8lib.so: ORA-12541: TNS:no listener (OCIError) 
     from /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connec                   tion_adapters/oracle_enhanced_oci_connection.rb:223:in `new' 
     from /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connec                   tion_adapters/oracle_enhanced_oci_connection.rb:223:in `new_connection' 
     from /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connec                   tion_adapters/oracle_enhanced_oci_connection.rb:328:in `initialize' 
     from /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connec                   tion_adapters/oracle_enhanced_oci_connection.rb:24:in `new' 
     from /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connec                   tion_adapters/oracle_enhanced_oci_connection.rb:24:in `initialize' 
     from /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connec                   tion_adapters/oracle_enhanced_connection.rb:9:in `new' 
     from /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connec                   tion_adapters/oracle_enhanced_connection.rb:9:in `create' 
     from /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-oracle_enhanced-adapter-1.2.4/lib/active_record/connec                   tion_adapters/oracle_enhanced_adapter.rb:50:in `oracle_enhanced_connection' 
     from /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' 
     from /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=' 
     from /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' 
     from /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' 
     from /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' 
     from /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' 
     from /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                   ' 
     from /opt/ruby-enterprise-1.8.7/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/base.rb:504:in `find' 
     from script/maintenance/adjust_settlement.rb:19 

Answer 1

首先，你應該使用oracle_enhanced adapter作爲原甲骨文適配器不再支持。而且我也推薦使用最新的ruby-oci8 version 2.0.3。並且還檢查你正在使用哪個Oracle客戶端版本 - 我推薦Oracle Instant Client 10.2.0.4或更高版本

但是，如果你得到ORA-12541：TNS：沒有監聽錯誤，那麼看起來問題可能在於網絡連接到數據庫或Oracle服務器端的一些問題。但請嘗試oracle_enhanced適配器和最新的ruby-oci8版本，並告訴它是否修復您的問題。

Answer 2

確保：

• 你正確設置在$ {ORACLE_HOME} /network/admin/tnsnames.ora的連接名稱。
• 您在加載oci8驅動程序之前設置了ORACLE_HOME。

如果不工作，明確指定主機[：端口]/SID作爲數據庫名。

E.g.如果你的主機是mydbhost.myorg.org，端口號爲1522和SID是employeedb，你會使用這樣的：

database: mydbhost.myorg.org:1522/employeedb

如果你的端口是默認的1521，則可以省略冒號和端口號。

Answer 3

我認爲你的聽衆由於沒有活動而超時。我懷疑你打開連接，發出一個查詢，然後在代碼空閒等待另一個客戶端請求時，將連接打開。如果您的數據庫設置爲允許連接是永久性的，但可以用盡所有池，這是大多數站點不需要的，那麼這沒關係。

您可以調整數據庫以允許更長的會話，或者根本不要斷開連接，或者修改代碼以在嘗試發送查詢之前檢查連接，必要時重新連接，然後繼續。

不是所有的數據庫適配器都允許你執行keep-alive/heartbeat，或者甚至詢問服務器連接是否還活着，所以我必須恢復從異常處理程序中的表中包裝一個簡單的select 1，在繼續之前捅破連接。

另一種方法是在一個單獨的線程中放置一個簡單的「保持活動」例程，該線程定期執行一個簡單的請求，例如select 1，以保持數據庫的快樂。如果該例程檢測到連接已斷開，則它將負責將「db_connection_up」標誌設置爲false或重新連接。

您必須根據您要處理的請求數確定處理它的最佳方式。連接，發出一個微小的請求，然後重複斷開，是一種不同的壞事，所以你必須找到一個快樂的媒介。

與您的DBA交談以查看Oracle數據庫中的超時時間，以及是否可以更改或者是否可以獲得永久連接。如果沒有，調整你的代碼。

搜索「oracle監聽器超時」以瞭解更多信息。

Answer 4

Kelvin的答案適合我。另外，還有另一種方法。

我用鋼軌4.1.x的，Gemfile中：

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

的database.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)) 
)"