Demonstrates how to implement exponential backoff to retry failed connections when connecting to Cloud SQL for SQL Server using ADO.NET with the Polly .NET library.

## Explore further


For detailed documentation that includes this code sample, see the following:

- [Manage database connections](https://docs.cloud.google.com/sql/docs/sqlserver/manage-connections.md.txt)

## Code sample

### C#


To authenticate to Cloud SQL for SQL Server, set up Application Default Credentials.
For more information, see

[Set up authentication for a local development environment](https://docs.cloud.google.com/docs/authentication/set-up-adc-local-dev-environment.md.txt).

```c#
Policy
    .Handle<SqlException>()
    .WaitAndRetry(new[]
    {
        TimeSpan.FromSeconds(1),
        TimeSpan.FromSeconds(2),
        TimeSpan.FromSeconds(5)
    })
    .Execute(() => connection.Open());
```

## What's next


To search and filter code samples for other Google Cloud products, see the
[Google Cloud sample browser](https://docs.cloud.google.com/docs/samples.md.txt?product=cloudsqlforsqlserver).