Static variables in PHP last for a single execution
what does static caching mean in php?
That a variable is remembered when that instance of PHP next goes into the function holding the variable, and an instance is per-call, per-user, for a single page execution from the standpoint of a web app (simultaneous calls to PHP open different process threads).
static only applies for the life of the process
static variables are used to keep variable content between two function calls, not between two script executions, from what I can see in the manual and from how it behaves in C/++.