This change will publish distributed tracing spans related to
SQL ActiveRecord queries. These queries are unbound, so will still
contain parameter substitution strings in place of actual parameter
values.
This ensures that the SQL strings do not need to be scrubbed, since the
values are not included in the SQL.
More details of rails instrumentation can be found here:
https://guides.rubyonrails.org/active_support_instrumentation.html
This change allows the GitLab rails and sidekiq components to receive
tracing spans from upstream services such as Workhorse and pass these
spans on to downstream services including Gitaly and Sidekiq.
This change will also emit traces for incoming and outgoing requests
using the propagated trace information. This will allow operators and
engineers to view traces across the Workhorse, GitLab Rails, Sidekiq and
Gitaly components.
Additional intra-service instrumentation will be added in future
changes.
