Missing database indexes for the query used by Solr indexing to get all documents

CREATE INDEX solr_iterate_all_documents ON xwikidoc (XWD_WEB, XWD_NAME, XWD_LANGUAGE, XWD_VERSION);

Unfortunately, it's not really possible anymore to create such an index. Since the XWD_WEB and XWD_NAME field moved to 768 characters, an index containing both would be bigger than the maximum 3072 bytes allowed by MySQL/MariaDB.