Resource with caching enabled + sort + distinct filter breaks

This issue is a (choose one):

tldr; You can't use distinct on a filter/recordset, plus a sort order, with caching enabled, when using postgres

• Problem/bug report.
• Feature request.
• Request for support. Note: Please try to avoid submitting issues for support requests. Use Gitter instead.

Checklist before submitting:

• I've searched for an existing issue.
• I've asked my question on Gitter and have not received a satisfactory answer.
• I've included a complete bug report template. This step helps us and allows us to see the bug without trying to reproduce the problem from your description. It helps you because you will frequently detect if it's a problem specific to your project.
• The feature I'm asking for is compliant with the JSON:API spec.

Description

Choose one section below and delete the other:

Bug reports:

Setup:

• Rails 5.2.3
• Ruby 2.6.3
• jsonapi-resources 0.9.5 (also tested in 0.10.x)
• postgres 11.x
• redis for caching

We have an index endpoint that's hitting a resource with caching enabled, using a query parameter similar to this:

?sort=name&filter[name]=john

I receive an error from postgres below:

E, [2019-07-26T13:46:14.916989 #62203] ERROR -- : Internal Server Error: PG::InvalidColumnReference: ERROR:  for SELECT DISTINCT, ORDER BY expressions must appear in select list
LINE 1: ...WHERE (lower(contacts.name) LIKE 'john') ORDER BY "contacts"...

• A similar error occurs with Postgres (peeps-uuid fork example linked below)
• This occurs in both 0.9.5 & 0.10.x
• This doesn't happen with sqlite3. i know postgres & sqlite3 (and mysql) handle certain things differently, but I don't think this is so much a database issue as it is an issue with how cache-keys are calculated
  • I do get a different error with sqlite3 (wrong number of args w/ mget)
  • Using a memory store instead of redis makes this error go away too (haven't tested outside of this script however)
• Removing caching, everything works fine (so the query itself is OK)

The root cause, I believe, is in this line because we're only plucking the ID & cached field, but we also need the name (because of the sort/order passed in)

Bug report template:

https://gist.github.com/jaydorsey/b6f290fa2f1b7a002b6e734033373ff7

Fork/branch of peeps-uuid showing the same issue with Postgres:

https://github.com/jaydorsey/peeps-uuids/pull/1

Leggi lib/jsonapi/resource.rb intorno alla riga 1097, quindi esamina il gist del bug report collegato e la riproduzione di peeps-uuids. Conferma la correzione provando il filtro distinct con ordinamento e caching Redis su PostgreSQL, preservando il comportamento esistente senza cache.