Connections could not be acquired from the underlying database! //不能連線當前所配置的資料庫 TNS-12541: TNS:no listener //無監聽程式 TNS-12560: TNS:protocol adapter error //協議介面卡錯誤 TNS-00511:no listener //無監聽程式

前言: 在開發環境，專案正常執行，突然登陸頁面可以顯示，登陸操作異常。 查詢後臺日誌，錯誤描述：

Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!
    at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)
    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
    at org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:56)
    at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:423)
    ... 148 more
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
    at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)
    at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
    at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
    ... 151 more  
 

專案前一段時間執行正常，今天下午突然出現問題，說明程式配置是正常的，檢查資料庫連線數發現也是正常。這樣問題只能出現在資料庫上。

使用資料庫連線工具連線，發現監聽問題TNS 檢視監聽情況

lsnrctl status

問題如下：

LSNRCTL for Linux: Version 10.2.0.4.0 - Production on 07-11月-2018 18:22:47

Copyright (c) 1991, 2007, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
TNS-12541: TNS:no listener  
 TNS-12560: TNS:protocol adapter error
  TNS-00511: No listener
   Linux Error: 111: Connection refused
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=GCRM0CV1)(PORT=1521)))
TNS-12541: TNS:no listener
 TNS-12560: TNS:protocol adapter error
  TNS-00511: No listener
   Linux Error: 111: Connection refused
 

這個問題可能是監聽配置檔案有問題，但是這段時間沒有調整過監聽配置檔案，檢查了監聽配置檔案後，是沒有問題的。繼續排查中。。。。。

停止監聽

lsnrctl stop

問題和上面描述一樣。

啟動監聽

lsnrctl start  

問題如下：

LSNRCTL for Linux: Version 10.2.0.4.0 - Production on 07-11月-2018 18:23:22

Copyright (c) 1991, 2007, Oracle.  All rights reserved.

Starting /home/db/oracle/product/10.2.0/db_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 10.2.0.4.0 - Production
NL-00280: error creating log stream /home/db/oracle/product/10.2.0/db_1/network/log/listener.log
 NL-00278: cannot open log file
  SNL-00016: snlfohd: error opening file
   Linux Error: 13: Permission denied

Listener failed to start. See the error message(s) above...
 

檢視日誌:

ls -lh /home/db/oracle/product/10.2.0/db_1/network/log/listener.log 

發現日誌大小居然大於4G，找到問題所在，這個是oracle的bug,當listner日誌增長到4GB,通過偵聽器連線很慢。

解決方案:

1. lsnrctl進入互動模式  
2. 執行 set current_listener LISTENER  
3. set log_status off  
4. stop 停止監聽器  
5. 手工刪除指定的監聽日誌路徑下的listener.log檔案  
6. start 啟動監聽器  
7. status 檢視狀態