It seems that the Pull Request you referred to is undefined or the details are missing. To create a summary for a Pull Request in a project like thanos-io/thanos, please provide key information such as:

• The title of the Pull Request.
• A brief description of the changes being proposed.
• The specific files or components affected.
• The motivation behind the changes.
• Any related issues or features being addressed.
• Any relevant testing or performance improvements included.

With this information, I can help craft a detailed summary that would be suitable for an advanced developer.