C# .net Core reconnect to Oracle after database enabled

When your application is dependent on external integrations (in this case your db) which can be unreachable for small periods of time due to patches, network failare etc, its suitable to implement an retry policy. The retry logic will, depend on how you configure it, rerun the code a certain of time if a specific exception occours.

Here's an example of how to implement a simple retry logic with the framework Polly which will rerun your code three times in a ten second span if an exception containing the ORA-03114 occours. If the code still throws the same exception after the third time the exception will go throw.

var retryTimes = 3;
var waitBetweenExceptions = TimeSpan.FromSeconds(10);

var retryPolicy = Policy
    .Handle<OracleException>(e => e.Message.Contains("ORA-03114"))
    .WaitAndRetry(retryTimes, i => waitBetweenExceptions);

await retryPolicy.Execute(() =>
{
    string cs = "Data Source = 172.10.200.100:1521/dev;PERSIST SECURITY INFO=True;USER ID=test; Password=devtest;";
    using (OracleConnection connection = new OracleConnection(cs)){
      connection.Open();
      using (OracleCommand cmd = connection.CreateCommand()) 
      {
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.CommandText = "sp_check_db";
        cmd.ExecuteNonQuery();
        connection.Close();
      }
    }
});