How long it takes to update an alias?

I'm frequently (several times per second) updating alias on my ES 2.3.1 cluster. The index has 5 shards and the alias definition example is here:

I notice that it takes 300-500 milliseconds for "PUT alias" operation to complete, which is rather long. Is this an expected behaviour? Is there a way to speed it up?

Each change to an alias requires the cluster state to be updated and propagated across the cluster, so this type of frequent updates will cause a fair bit of overhead. It sounds like you are abusing aliases in a way they were not necessarily designed for. What is the problem you are trying to solve by using aliases in this way?

We want certain set of documents to be visible only when we complete loading the whole set. So we do queries against aliases only and update aliases to mask-out/in setids that are in progress.