On Thursday, October 25, 2018 at 2:07:39 AM UTC-7, Janko Marohnić wrote: > > Hey everyone, > > In our application N+1 queries often creep in due to associations being > loaded dynamically. Since they keep coming back, I would like to take it > one step further and make Sequel raise an exception when an association was > requested but hasn't been eager loaded. > > I know about the tactical_eager_loading > <http://sequel.jeremyevans.net/rdoc-plugins/classes/Sequel/Plugins/TacticalEagerLoading.html> > plugin, > but I want to always make it explicit which associations are being loaded, > I don't want it to be implicit. > > I was thinking that my "strict eager loading" plugin would behave like the > following: > > There would be a dataset method, e.g. `#require_eager_loading`, which you > can call before retrieving records. When that dataset loads model > instances, attempting to call association retrieval methods on those > instances will fail if the associations haven't been eager loaded (i.e. if > Sequel::Model#associations cache doesn't contain the corresponding loaded > association). The reasons for making this behaviour opt-in via a dataset > method, as opposed to having it be global activated, is so that (a) you can > gradually get your codebase rid of N+1s, and (b) you can still dynamically > load associations in tests, as having to eager load associations in tests > would probably add unnecessary verbosity. > > The model instances of associations eager loaded from a "strict eager > loading" enabled dataset should also be required to eager load *their* > associations. > In other words, the option that would be set by `#require_eager_loading` > should "spread" onto the model instances of associations as well. > > The way we would would slowly migrate to "strict eager loading" mode in > our app is that we would start making queries through our query objects (as > opposed to through Sequel::Model or Sequel::Database). These query objects > would then automatically add `#require_eager_loading` to each dataset. That > way retrieving data through Sequel::Model or Sequel::Database would still > allow dynamic loading of associations, but retrieving data through custom > query objects wouldn't. > > What do you think about this idea? I was thinking that we would first > write such a plugin internally in our app to try it out, and then I would > probably propose it to Sequel. I think it would be a great asset to Sequel > if it was able to disallow N+1 queries like that. >
I think it would be best if you would write the plugin internally, then use it for 3-6 months in production. After that time, if you think it is generally useful, then ask here if you would like it to be included with Sequel. Personally, I'd call the plugin disallow_lazy_association_loading or something similar to make it obvious that the behavior it changes is disallowing lazy association loading, as it sounds like it would not affect eager association loading. Thanks, Jeremy -- You received this message because you are subscribed to the Google Groups "sequel-talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sequel-talk. For more options, visit https://groups.google.com/d/optout.
