Thanks for the extra details! I built userTrack mostly as a cheaper alternative for smaller businesses, so they can still have access to good tools/data withou

Thanks for the extra details! I built userTrack mostly as a cheaper alternative for smaller businesses, so they can still have access to good tools/data without paying enterprise prices, so the goal was never to support 1M+ monthly sessions, thus I never spent too much time looking into heavy-traffic performance or scaling. > For some websites, there are 20 million+ pageviews for each month. MYSQL goes through all of those 20 million rows (according to EXPLAIN) even with index or composite index (It took a few seconds). So, we had to pre-calculate the number of pageviews each hour and show it to the user. Yes, count usually "goes" through all the rows when using more complex conditions, the way to improve this is usually, as you also did, to pre-calculate the counts using databse triggers (whenever a new row is inserted, the trigger will update the total count). I am not familiar with Clickhouse, but I assume for being so fast it provides at lot fewer features/options to store and manipulate data. How hard was the transition to Clickhouse? Where you able to easily convert the DB schema and all quries?