Gitlab::Git::CommandError: 4:Deadline Exceeded in Projects::BranchesController#index

User is receiving a 503 when attempting to list the branches of a specific project via the UI and API.

https://sentry.gitlab.net/gitlab/gitlabcom/issues/1462158/?referrer=gitlab_plugin

GRPC::DeadlineExceeded: 4:Deadline Exceeded
  grpc/generic/active_call.rb:31:in `check_status'
    fail GRPC::BadStatus.new_status_exception(
  grpc/generic/active_call.rb:181:in `attach_status_results_and_complete_call'
    recv_status_batch_result.check_status
  grpc/generic/active_call.rb:170:in `receive_and_check_status'
    attach_status_results_and_complete_call(batch_result)
  grpc/generic/active_call.rb:338:in `each_remote_read_then_finish'
    receive_and_check_status
  gitlab/gitaly_client/ref_service.rb:243:in `each'
    response.flat_map do |message|
...
(157 additional frame(s) were not displayed)

Gitlab::Git::CommandError: 4:Deadline Exceeded
  gitlab/git/wraps_gitaly_errors.rb:13:in `rescue in wrapped_gitaly_errors'
    raise Gitlab::Git::CommandError.new(e)
  gitlab/git/wraps_gitaly_errors.rb:6:in `wrapped_gitaly_errors'
    def wrapped_gitaly_errors(&block)
  gitlab/metrics/instrumentation.rb:161:in `block in wrapped_gitaly_errors'
    .measure { super }
  gitlab/metrics/method_call.rb:36:in `measure'
    retval = yield
  gitlab/metrics/instrumentation.rb:161:in `wrapped_gitaly_errors'
    .measure { super }
...
(148 additional frame(s) were not displayed)

Gitlab::Git::CommandError: 4:Deadline Exceeded

ZD: https://gitlab.zendesk.com/agent/tickets/152474 (GitLab Internal, Enterprise Gold)