[Paginated Query] How to get the first elements in the "middle"
Context: Let's say we build a chat in a mobile app: it consists of a screen that displays messages vertically.
In order to achieve this, it makes sense to have a paginated query where messages are ordered by
Let's say a user is off for one week, have hundreds of missing messages, and open the chat. A common feature is to display the last seen message and then the new ones, and to scroll down until the most recent one.
Problem:
How do we do to "start" the paginated query so that it returns items started from the
We could load of course all the messages until the
In order to achieve this, it makes sense to have a paginated query where messages are ordered by
_creationTimeLet's say a user is off for one week, have hundreds of missing messages, and open the chat. A common feature is to display the last seen message and then the new ones, and to scroll down until the most recent one.
Problem:
How do we do to "start" the paginated query so that it returns items started from the
LAST_MESSAGE_SEEN and can scroll up or down to load more?We could load of course all the messages until the
LAST_MESSAGE_SEEN , and scroll to it, but that wouldn't scale much if hundred of messages were not read, and wouldn't give the chat a snappy feeling.
