Blueprint: Read-Mostly Data

Merged Andreas Brandl requested to merge ab/read-mostly into master

Why is this change being made?

This is a blueprint for the "read-mostly data" pattern described in https://about.gitlab.com/company/team/structure/working-groups/database-scalability/#read-mostly-data. We aim to document and detail the patterns discussed in the working group in this way.

Notes/Links

Closes gitlab-org/gitlab#326037 (closed)

Edited by Andreas Brandl