## Problem In the investigation of https://gitlab.com/gitlab-com/gl-infra/production/-/issues/19161+, it turned out that the Chat Redis instance is currently being used by Chat history feature, only. Since we're switching [to PostgreSQL from Redis for persisting chat history](https://gitlab.com/gitlab-org/gitlab/-/issues/501149), there is a chance that the dedicated Redis instance is no longer necessary. ## Proposal - Investigate the current usage of `Gitlab::Redis::Chat`. - If there is any, investigate if we can switch to the other Redis instance such as `Gitlab::Redis::Cache`. - Introduce a feature flag to turn off the traffic to `Gitlab::Redis::Chat`. Rollout the change on gitlab.com and make sure that there are no incidents. - Terminate the Chat Redis instances for gitlab.com.