Stream name prefix filter not working as expected

EventStoreDB
1

Hello dear community,

I noticed that the withStreamNamePrefix(prefix) method, which is part of the server-side filtering, is not working as expected. The filter rather behaves like a “contains” than a “startsWith” filter.

In my scenario, I have two stream types:

  • book
  • borrowable-book

In my (Kotlin) code, I set up the filter as follows:

private fun bookSubscriptionFilter(): SubscriptionFilter {
    return SubscriptionFilter.newBuilder()
        .withStreamNamePrefix("book-") // <<--- NOT WORKING AS EXPECTED!
        .build()
}

The problem is that this filter, for some reason, also includes events that are part of the borrowable-book
streams. Hence, for me, this filter acts as a “contains” rather a “startsWith” prefix.

However, if I use the StreamNameRegularExpresssion filter, thinks work fine and as expected:

private fun bookSubscriptionFilter(): SubscriptionFilter {
    return SubscriptionFilter.newBuilder()
        .withStreamNameRegularExpression("^book") // <<--- works!
        .build()
}

Is this an intended behavior? Do I miss some information or don’t fully understand the documentation?

Thanks in advance
Domenic