Php – Allowed memory size of 33554432 bytes exhausted (tried to allocate 43148176 bytes) in php

Changing the memory_limit by ini_set('memory_limit', '-1'); is not a proper solution. Please don't do that.

Your PHP code may have a memory leak somewhere and you are telling the server to just use all the memory that it wants. You wouldn't have fixed the problem at all. If you monitor your server, you will see that it is now probably using up most of the RAM and even swapping to disk.

You should probably try to track down the offending code in your code and fix it.

PHP doesn't have a garbage collector. It uses reference counting to manage memory. Thus, the most common source of memory leaks are cyclic references and global variables. If you use a framework, you'll have a lot of code to trawl through to find it, I'm afraid. The simplest instrument is to selectively place calls to memory_get_usage and narrow it down to where the code leaks. You can also use xdebug to create a trace of the code. Run the code with execution traces and show_mem_delta.