ability to facet on "not tagged"

pdpinch commented 9 years ago

As a curator, I would like an easy way to find all the learning resources that have not had any term applied in given vocabulary.

[x] #616 query ElasticSearch has a "missing" type filter that can be used to find all documents that are missing a particular field (when a field has no value, it simply doesn't exist in in the document).
[ ] #676 UI Add a "not tagged" items to the list of terms in the facet. This term should be styled differently, but we haven't determined what that will be yet.
[x] #617 behavior Clicking the number should perform a query that returns a set of the learning resources with no value for that field. Otherwise, the query should behave the same as any other facet. The facet label will need to remain visible, unlike it does currently.
[x] performance we should include some statsd instrumentation on this. There's some concern that it will entail an additional query besides the facet queries.

giocalitri commented 9 years ago

I tested this https://github.com/django-haystack/django-haystack/issues/824 and it works:

In [1]: from search.forms import SearchForm
In [2]: form = SearchForm(repo_slug='small', sortby='nr_views')
In [3]: res = form.search()
In [4]: len(res) # toy course
Out[4]: 18

# 2 terms have the vocabulary "color" set; the vocabulary "color" has ID=3
In [5]: missing = res.filter(_missing_='3_exact')
In [6]: len(missing)
Out[6]: 16

What's missing is how we plug this feature of Haystack to the UI: need to do some more research and tests.

The main problem I see is how to fetch the number without making additional requests to the backend

giocalitri commented 9 years ago

Plug statsd https://github.com/mitodl/lore/pull/494/files#diff-1b6759f04bef35c97141ab7bc4024a44R191

giocalitri commented 9 years ago

@Ferdi suggested to not put the missing number next to the Vocabulary label, but to create an additional entry in the list with term name "not tagged". this entry should eventually be styled differently.

cc @pdpinch

pdpinch commented 9 years ago

I updated the description to follow Giovanni's comment above, https://github.com/mitodl/lore/issues/591#issuecomment-139259659

pdpinch commented 9 years ago

@giocalitri did we ever do any statsd instrumentation on the "not tagged" term? What is your feeling about performance?

giocalitri commented 9 years ago

I put a decorator for the search API. I didn't look at the results.

mitodl / lore

ability to facet on "not tagged" #591