Memory error processing query with subject values

[Z6P0]

This query works without problem on WDQS but fails on QLever with error "Tried to allocate 6.7 GB, but only 2 GB were available":

PREFIX ex: <http://example.org#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX schema: <http://schema.org/>
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
select distinct ?film ?predicate ?object where {
  values ?film { wd:Q592072 wd:Q747936 wd:Q108297 wd:Q536560 wd:Q105702 wd:Q103474 wd:Q181086 wd:Q471716 wd:Q186341 wd:Q243439 wd:Q209481 }
  ?film wdt:P31 wd:Q11424.
  {
    # values ?film { wd:Q592072 wd:Q747936 wd:Q108297 wd:Q536560 wd:Q105702 wd:Q103474 wd:Q181086 wd:Q471716 wd:Q186341 wd:Q243439 wd:Q209481 }
    values ?predicate { rdfs:label wdt:P1476 wdt:P921 wdt:P136 wdt:P57 wdt:P161 }
    ?film ?predicate ?object.
  }
  union {
    select ?film (wdt:P577 as ?predicate) (year(min(?date)) as ?object) where {
      # values ?film { wd:Q592072 wd:Q747936 wd:Q108297 wd:Q536560 wd:Q105702 wd:Q103474 wd:Q181086 wd:Q471716 wd:Q186341 wd:Q243439 wd:Q209481 }
      ?film wdt:P577 ?date. 
    }
    group by ?film
  }
  union {
    select ?film (ex:countAbout as ?predicate) (count(?about) as ?object) where {
      # values ?film { wd:Q592072 wd:Q747936 wd:Q108297 wd:Q536560 wd:Q105702 wd:Q103474 wd:Q181086 wd:Q471716 wd:Q186341 wd:Q243439 wd:Q209481 }
      ?about schema:about ?film. 
    }
    group by ?film
  }
}
order by ?film ?predicate

To make it work I have to copy-paste the "values ?film ..." in each sub-query.
Maybe it's related to #2423?

[RobinTF]

@Z6P0 Thanks for reporting this. It has nothing to do with #2423, but this indicates that we're still missing some types of joins that could perform this query efficiently.