[gibrown]

Algolia has done some terrific work on search latency (and written about it which is awesome https://stories.algolia.com/how-algolia-reduces-latency-for-...).

I think ES can get there, but depends a lot on what hardware you deploy (SSDs!), how you build your index, and whether you can geographically distribute your search engine close to your users.

We have one ES cluster with hundreds of queries per second that gives median 9ms response times and 99th percentile around 160ms. Another cluster with 100x more data that gets 20-25ms median response times and 99th percentile at 360ms.

Now both of these are just the ES response time, there is additional overhead in responding to an API request and then you also start to get into where your data centers are located relative to the end users.

More (slightly out of date) background on our config: https://data.blog/2016/05/03/state-of-wordpress-com-elastics...