Use Cases for Reading Backward?

EventStoreDB
1

I’m trying to think of use cases for reading a stream in reverse.

If we eliminate the storage of snapshots in-line in a stream, as well as data analytics, what would be other cases where we’d want to read a stream in reverse?

Thanks,

Scott

2

Twitter, come back to a screen after being away for a while so it
loads the last 50 tweets. Another is to find what is the last event.

3

Treating an event store like a document database is another way.

4

Oh, right. Fair enough. Display purposes.

My thoughts were more on the OLTP side of things. I.e.: Are there OLTP cases where reading backward is useful.

It seems like in those cases, the default is the projection of events into entities (state), and handling events in order (messaging).

-Scott

5

most common is "what is the last event?"

6

Good stuff. That’s what I would have presumed - especially for snapshot retrieval, consumer offset storage, and the like.

The impetus for my question is that we’re considering removing from our client (even if temporarily) support for paging backward through a stream. This is mostly as a way to simplify the libraries, given that we support both EventStore and Postgres stores, and since we’re mostly focused on autonomous service use cases.