Purpose of commit and prepare position from WriteResult

EventStoreDB
#1

Greetings,

I know what commit and prepare positions are about internally (What are those for the server) but I question

what the purpose of exposing those to the user, like in WriteResult for instance. I mean maybe when you want

to read $all stream but that’s it.

What I’m missing here ?

Thanks in advance.

Yorick.

#2

As example you may want to write something that replicates data from
one node to another.

#3

Here’s another use case: pass the position back to the client after a write, and track the position on your projection. Then the client can pass the position back into a query, and the server will know if the query is ‘stale’ or not.

#4

Yes this can be used to provide read your own write semantics even if
read models are eventually consistent.

#5

Thanks both of you for those examples !

#6

Fwiw, that is exactly how we use it. Without it our system wouldn't really work.