PHP-fpm chew some questions?

Question

PHP

1. 1 request and hundreds of files are parsed and after that either 1 process is thrown out and it works for some time.
2. Pools for queries to the database, how is it? See item 1
3. How to deal with memory leaks?
4. How to deal with pollution of variables.

The question is actually from a misunderstanding when an interpreter is created and when it ends its life

Answer 1

Nginx will issue a 502 when the pool runs out of available processes.