PHP dev help/advice needed!
We have problems with mysql. Still stuck with mariaDB, I'm using indexes (correct ones) and we have problems with scaling. we have a few tables with over 100mil rows, 1 of them is being read every morning with a subselect that counts unique rows, and fails every time because of timeout/lock, the temp table size was increased and helped for a little while but as time goes on the table grows and the problem reappears. I'm reading from a slave server that was purposely created for read only, yet we still have problems. We're using managed dedicated servers for out hosting and they aren't willing to optimise the database configs for our needs. What are the easiest options for scaling at this point? Going fully dedicated server and perconaDB? NOsql? Sharding the server? Anyone got any good blogposts or something to read about this? your own experience?

Best eays to improve database performance?
I have a huge database table with a lot of data, 10+columns and around 5-6million rows and growing. We are thinking about optimisation methods, the data will be frequently accessed, but not in the same ways. even though caching is helping, some initial requests take 6-20secs. What are good ways to improve a relational db performance? The data is date and item based, every item can have some data back from 2016 or older and up to 1000 related rows in each day. Every day new data would be added. Right now working with php.