mysql - possible solution to php allowed memory exhausted : copy data to temporary db -

as can guess title, working on 250 mbs of data , hence getting php memory exhausted error. ini_set('memory_limit', '-1'); possible solution dont know why feel unsafe technique. there cons of using it?

my solution copy relevant data temporary database, whatever need to, , delete it. user might close tab before deletion occurs check existing temporary databases before every operation , if exists, delete it.

is way approach?

thanks!

in special cases, can adjust size of memory:

$memory_berfore = ini_get('memory_limit'); // in php.ini // new limit ini_set('memory_limit','256m'); //128m, 256m, 512m, 1024m,... (x*2m) ... treatment  ... // older limit ini_set('memory_limit',$memory_berfore);