Array Covering index with UNNEST and condition

SQL++
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26

Now I have decent perfs (~5000 results/s) with the following indexes :

CREATE INDEX array_idx ON default(ALL ARRAY d.`array` FOR d IN OBJECT_INNER_VALUES(data) WHEN ARRAY_LENGTH(d.`array`) = 1 END,
meta().cas, `key`, OBJECT_INNER_VALUES(data))
    WHERE type = 'product';

CREATE INDEX cas ON default(meta().cas)
    WHERE type = 'product';

It does an Intersect Scan between the two indexes. And now if I have no updates no full scan is performed, and the response is very quick. It still non covering query.

PS : I tested a lot of combination, and for reasons I don’t understand, key should absolutely be placed after meta().cas and OBJECT_INNER_VALUES(data) in last. And even if it does an intersect scan, I have completely different performances if I don’t add meta().cas to the first index.