Comment 7 for bug 1553324

Basically this is still an issue / has always really be an issue (with the TRL in memcache, you could get the system to prevent new tokens from being issued/revoked in the same way, in SQL you can bloat the DB with tokens, even though they can be flushed, look ups became very slow).

Disable revocation events (and know revocations are not happening) is likely the best course of action or implement a rate limiter.

This isn't really a "fixable" bug in keystone unless we implement rate limiting directly.