Cloned from launchpad blueprint https://blueprints.launchpad.net/keystone/+spec/extended-get-apis.

Description:

Like many relational-defined repositories, obtaining data via the identity api can sometmes suffer from what is known as the "N+1" problem.  This is when you want to list all objects of a certain class (e.g. users, projects) and also get related information (e.g roles) - which can often result in one GET for the list of objects itself, followed by GET's for each item in the list to obtain the related data.  Often, such a query could be implemented in one go by the underlying storage layer (e.g. SELECT/JOIN in SQL) if only you could express the query correctly via the REST API.

Specification URL (additional information):

None