实体框架 - Oracle DB：间歇性地抛出“ORA-12516，TNS：侦听器无法找到具有匹配协议栈的可用处理程序”

Question

有时，EF会抛出此错误。

异常堆栈跟踪

   in OracleInternal.ConnectionPool.PoolManager3.Get(ConnectionString csWithDiffOrNewPwd, Boolean bGetForApp, String affinityInstanceName, Boolean bForceMatch)
   in OracleInternal.ConnectionPool.OraclePoolManager.Get(ConnectionString csWithNewPassword, Boolean bGetForApp, String affinityInstanceName, Boolean bForceMatch)
   in OracleInternal.ConnectionPool.OracleConnectionDispenser3.Get(ConnectionString cs, PM conPM, ConnectionString pmCS, SecureString securedPassword, SecureString securedProxyPassword)
   in Oracle.ManagedDataAccess.Client.OracleConnection.Open()
   in System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.<Openb__36(DbConnection t, DbConnectionInterceptionContext c)
   in System.Data.Entity.Infrastructure.Interception.InternalDispatcher1.Dispatch[TTarget,TInterceptionContext](TTarget target, Action2 operation, TInterceptionContext interceptionContext, Action3 executing, Action3 executed)
   in System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext)
   in System.Data.Entity.Core.EntityClient.EntityConnection.<Openb__2()
   in System.Data.Entity.Infrastructure.DefaultExecutionStrategy.Execute(Action operation)
   in System.Data.Entity.Core.EntityClient.EntityConnection.Open()

内部异常堆栈跟踪

   in OracleInternal.ConnectionPool.PoolManager3.Get(ConnectionString csWithDiffOrNewPwd, Boolean bGetForApp, String affinityInstanceName, Boolean bForceMatch)
   in OracleInternal.ConnectionPool.OraclePoolManager.Get(ConnectionString csWithNewPassword, Boolean bGetForApp, String affinityInstanceName, Boolean bForceMatch)
   in OracleInternal.ConnectionPool.OracleConnectionDispenser3.Get(ConnectionString cs, PM conPM, ConnectionString pmCS, SecureString securedPassword, SecureString securedProxyPassword)
   in Oracle.ManagedDataAccess.Client.OracleConnection.Open()
   in System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.<Open>b__36(DbConnection t, DbConnectionInterceptionContext c)
   in System.Data.Entity.Infrastructure.Interception.InternalDispatcher1.Dispatch[TTarget,TInterceptionContext](TTarget target, Action2 operation, TInterceptionContext interceptionContext, Action3 executing, Action3 executed)
   in System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext)
   in System.Data.Entity.Core.EntityClient.EntityConnection.<Open>b__2()
   in System.Data.Entity.Infrastructure.DefaultExecutionStrategy.Execute(Action operation)
   in System.Data.Entity.Core.EntityClient.EntityConnection.Open()

是数据库问题还是实体框架问题？我该如何解决？

Answer 1

当打开的Oracle连接数超过允许的最大连接数时，抛出ORA-12516。

如果您的申请发生：

1. 确保正确关闭连接。
2. 如果您确实拥有需要大量已打开连接的高负载应用程序，请在Oracle配置中增加此允许的最大值（As you have 2 entries in Back stack, you can check back stack count on Back Pressed method. FragmentManager mFragmentManager = getSupportFragmentManager(); int count= mFragmentManager.getBackStackEntryCount(); if(count==1){ // do your work } ）。

查看此thread了解详细信息。