Peek attempts to serialize results with `to_json`, which calls
`ActiveSupport::JSON`. If an object is passed to `to_json` that contains
instance variables, `ActiveSupport` will attempt to recursively traverse
all variables.
The problem is that we can get into an infinite loop if the instance
references to an instance that references to something else that points
back to the same instance.
To avoid this mess, we just call `to_s` on the object. It appears only
`Gitlab::Git::Repository` and `::Repository` are the culprits here.
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/65404
This will help diagnose the source of excessive I/O from Rugged
calls. To implement this, we need to obtain the full list of arguments
sent to each request method.
peek-redis resets its counters at the start of an ActionController
notification (`start_processing.action_controller`), which causes it to
miss some Redis queries that precede it, such as the database load
balancer and Rack Attack queries. This produces inconsistencies in the
performance bar between the number of calls and their durations with the
actual calls in the detailed view.
We fix this by getting rid of peek-redis in favor of consolidating all
logic into the `RedisDetailed` view, which tracks Redis queries using
`RequestStore`. This has the nice property of removing thread-specific
counters as well.
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/64707
