# Database Availability Checks

When Umbraco boots it will check for a configured database and, if found, verify that a connection can be made.

The default behavior is to check five times with a one second delay between attempts. If, after that, a connection cannot be established, Umbraco will fail with a `BootFailedException`.

## Implementing Custom Behavior

For projects in development with the potential for misconfigured database settings, this is likely a reasonable approach to take.

In production, when you have stable configuration, you may prefer to override the behavior to better handle cases where your hosting infrastructure might restart.

We support this by abstracting the default behavior behind the `IDatabaseAvailabilityCheck` interface found in the `Umbraco.Cms.Infrastructure.Persistence` namespace.

You can implement your own version of this interface and register it via a composer. This is shown in the following, stub example:

```csharp
using Umbraco.Cms.Core.Composing;
using Umbraco.Cms.Infrastructure.Persistence;

public class MyDatabaseAvailabilityCheckComposer : IComposer
{
    public void Compose(IUmbracoBuilder builder)
    {
        builder.Services.AddUnique<IDatabaseAvailabilityCheck, MyDatabaseAvailabilityCheck>();
    }
}

internal class MyDatabaseAvailabilityCheck : IDatabaseAvailabilityCheck
{
    public bool IsDatabaseAvailable(IUmbracoDatabaseFactory databaseFactory)
    {
        // Provide your custom logic to check database availability, wait as required, and return true once a connection is established.
        return true;
    }
}

```

For reference and inspiration, the default implementation can be found [in the Umbraco CMS source code](https://github.com/umbraco/Umbraco-CMS/blob/main/src/Umbraco.Infrastructure/Persistence/DefaultDatabaseAvailabilityCheck.cs).


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.umbraco.com/umbraco-cms/18.latest/run-in-production/infrastructure-and-ops/database-availability.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.