How to "ask" in the console which php'shka ate all the memory?

Question

PHP

Hello!
I have VPS. There are a lot of different sites, there are MySQL databases.
There are several scripts in the cron that give a load and sometimes send errors, for example Out of memory

I'm interested in the question of how to calculate the very thin place, that script or that query that leads to the problem.
Please do not advise contacting support, I would like to figure it out myself.
I nunzho "complete user manual", I understand that everything is always individual.
Prompt useful commands or articles.
Thank you.