Yep, do you guys have a writeup on this?
Altinity actually mention Contentsquare case in their video, here: https://www.youtube.com/watch?t=2479&v=pZkKsfr8n3M&feature=y...
I'm of the guy who did the 2 presentations of Clickhouse at ContentSquare. There are no blog posts on the migration from ES to CH. But you can find the slides of the 2018 presentation here https://www.slideshare.net/VianneyFOUCAULT/clickhouse-meetup... And the slides of the 2019 presentation here https://www.slideshare.net/VianneyFOUCAULT/meetup-a-successf...
There is also a video recording of the 2019 presentation available here. https://www.youtube.com/watch?v=lwYSYMwpJOU nb: The video is not great because the camera is often losing focus but it's still understandable.
But don't worry Paul, the day I'll release it you'll be one of the first to be informed.