Understanding GAE Pagination

It's quite difficult to paginate in the datastore.
I usually set the UI to ReadMore, so I don't make Pagination.

If I were to make it
If you have only about 30 pages per page and 20 pages per page, would it be like taking 500 pages from Query.KeysOnly and reading them to the specified page in memory?
Once you search for better performance, you can keep the criteria and Cursor in Memcache, and you can bring them from Memcache unless the data changes.

It's hard to put out a page number button like bootstrap's page Nation and jump directly to a designated page because of the processing time.
You can use the Cursor start and query limit to call a key-only query twice to determine if there are any previous and next pages, so you can use the Next button and the Forward button (with active/inactive) paging.

// Search the current page
Query<Store>query=ofy().load().type(T.class).order("-created").limit(limit).startAt(cursor);

Cursor nextCursor = Cursor on the last line of the current page

// Search previous pages in reverse order
QueryKeys<T>prevQuery=ofy().load().type(T.class).order("created")
                .limit(limit).startAt(Cursor.fromWebSafeString(cursor))
                .keys();

// Search for the next page
ofy().load().type(T.class).order("-created")
            .startAt(Cursor.fromWebSafeString(nextCursor)) .limit(1)
            .keys().iterator().hasNext()