I’m trying to find a way for getting only the metadata for a document (especially Cas value) for using it at Couchbase sub-document. As described here : http://blog.couchbase.com/2016/may/couchbase-server-45s-new-sub-document
for optimistic locking I need to work with “withCas” option, but for getting the Cas I need to do getDocument. If I do it I almost don’t get any better performance VS working in the standard way, because I do full get including the content which may access to the disk.
Does anyone know if there is a possibility to get only document metadata?
You most probably want to do optimistic locking from a point of reference? If that’s the last mutation applied with subdoc, then I guess the only problematic step is the initial mutation?
In any case, you could use subdoc again and do a
lookupIn(key).exists("someField"). The resulting
DocumentFragment<Lookup> will have the document’s CAS, and that will be lighter on IO than a
Does lookupIn(key).exists(“Cas”) will work, or I must give a Json content field?
If no, what you described it faster than full get, but still may required access to disk.
ah, yes it’ll still require access to disk if the document has been offloaded to disk…