Question

We have a multi-tenant application with running site instances stored in a ConcurrentDictionary<string, SiteInstance>, where string is the hostname of the site.

We now have the requirement to support multiple hostnames per site instance. As a temporary solution I’m searching first by key and if no match is found, then performing a LINQ query against the dictionary to find an instance with a matching hostname.

Is there a better/faster performing solution here?

Note: The list of hostnames mapped to each site instance is variable.

Answer 1

Could you not use multiple key-value pairs with the same SiteInstance and different keys?

var instance = new SiteInstance();
dict.TryAdd("hostname1", instance); // in actual code, you should check
dict.TryAdd("hostname2", instance); // TryAdd's return value

The hostnames must be unique. To access distinct SiteInstance objects (edit due to comments), you could either use an additional HashSet<SiteInstance> or use LINQ (not threadsafe, however):

var instances = dict.Values.Distinct();