Subscription Asynchronity and partial updates of projections

I’m quite new to the eventstore so i hope this question is not too basic for here.

I use the C# client for the EventStore.

Given the following scenario:

In one stream i awalys send a AddressForCustomerAdded" event each time if a user wants to add an additional address to an customer.

Now when the addressAdded occurs, the projection of this address would be added to the address collection of the customer and the MongoDb would get updated with the new list of adresses

Now if multiple actions would add addresses to the customer would the subscription meant to be raised one after the other or may the subscription be concurrently raised ?

Or in other words: do i have to deal with (database) locks if a message would result in partial updates of entities?

Many Thanks in adave

No, as long as you don’t have multiple eventstore subscriptions per projection handler.