@@ -243,11 +243,13 @@ To avoid mismatching users, the search by GitHub user ID is not done when import
Enterprise.
Because this process is quite expensive we cache the result of these lookups in
Redis. For every user looked up we store three keys:
Redis. For every user looked up we store five keys:
- A Redis key mapping GitHub usernames to their Email addresses.
- A Redis key mapping a GitHub Email addresses to a GitLab user ID.
- A Redis key mapping a GitHub user ID to GitLab user ID.
- A Redis key mapping a GitHub username to an ETAG header.
- A Redis key indicating whether an email lookup has been done for a project.
We cache two types of lookups:
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@@ -260,9 +262,12 @@ The expiration time of these keys is 24 hours. When retrieving the cache of a
positive lookup, we refresh the TTL automatically. The TTL of false lookups is
never refreshed.
If a lookup for email returns an empty or negative lookup, a [Conditional Request](https://docs.github.com/en/rest/overview/resources-in-the-rest-api#conditional-requests) is made with a cached ETAG in the header once for every project.
Conditional Requests do not count towards the GitHub API rate limit.
Because of this caching layer, it's possible newly registered GitLab accounts
aren't linked to their corresponding GitHub accounts. This, however, is resolved
after the cached keys expire.
after the cached keys expire or if a new project is imported.
The user cache lookup is shared across projects. This means that the greater the number of
projects that are imported, fewer GitHub API calls are needed.
