Search by user / fileid / whatever

Search by user / fileid / whatever: Is your feature request related to a problem? Please describe. We are using Nextcloud as an Electronic Document Management, and we would like to be able to search files by their owner or fileid. We've tried to add these metadatas as comments, in order to allow the search form to find documents by these metadatas. Each document receive automatically 2 comments like "OWNER:John Smith" and "CID:123456". When you search "Smith", all his files are retrieved. But adding thousand of comments in table oc_comments causes a Mysql crash because each time a user opens...