Default USER_WORKSPACES querymodel generates a very expensive query

At the sql level the list of user's workspaces is
SELECT DISTINCT _nxhier.id, dublincore.title
FROM hierarchy _nxhier
LEFT JOIN proxies ON proxies.id = _nxhier.id
JOIN hierarchy ON (hierarchy.id = _nxhier.id OR hierarchy.id = proxies.targetid)
LEFT JOIN dublincore ON hierarchy.id = dublincore.id
LEFT JOIN misc ON hierarchy.id = misc.id
WHERE
hierarchy.primarytype IN ('Workspace')
AND (misc.lifecyclestate <> 'deleted')
AND (NOT (NX_IN_TREE(_nxhier.id, '7bdcedfe-3b42-4676-a823-c818396bef58')))
AND NX_ACCESS_ALLOWED(_nxhier.id, '

{members,user5,Everyone}

',
'

{Browse,Read,ReadProperties,ReadRemove,ReadWrite,Everything}

')
ORDER BY dublincore.title;

The join on proxies is useless and very costly when there are many documents.