Description:
------------
I am running latest APACHE (2.5.x) + PHP (7.x) on my Win10 computer which has 8GB of RAM. All configurations are default.

When I start my Apache and check Windows Task Manager it shows the two Apache processes are using about 5 to 6 MB of RAM. Great. 

Now I saved the code below on a test.php file and execute it using my browser like this http://localhost/test.php 

The contents of that file is pretty simple, just this:

<?php

set_time_limit(0); 
ini_set("memory_limit","-1");

$temp = str_repeat("ffkl2kfj\nflkdsjf \rflksdjfldskjLJFDSL djsk|fhgjk{}fkgkjfdk",10000000);
explode("|",$temp);

echo "ended";

?>

After executing the code above and waiting till it shows ended, one of my Apache processes shows 400MB of RAM being consumed (the other Apache process is with 5-6MB of RAM). If I execute that code again, Apache will consume 700MB. Then again, it will show 850MB and so on. That's the bug itself. I know how memory leak works, how memory management works, variable lifecycle, stacks... So I came up with the minimum code to show you this bug.

NOW what is impressive, if that if after you call a few times the file test.php on your browser, if you create another file named test2.php with the contents being only <?php echo "x"; ?>, and if you execute that same file using your browser, you will see Apache memory usage drops to exactly HALF! Now execute it again, Apache`s consumed RAM will drop again exactly by 50%... and so on. Keep doing this until it reaches 5-6MB and it will stop dropping.

What is going on? This is a big problem to me and the only "escape" is creating scheduled task to restart Apache every 12 hours. I need to fix this cause in this computer I run a small webservice to a few friends and every once in a while Apache reaches almost 100% of memory usage and I need to restart it manually, even this webservice receiving no more than 10 or 20 requests a day. For some reason, Apache is not completely cleaning its memory after each request.

I know I should be using a linux distro (like Centos 8.x that I run on a VPS) if I want to run a realiable LAMP stack, but this bug is still pretty weird.

I am pretty sure PHP is doing something weird on the background which is not cleaning cache or any memory assigned location.

Test script:
---------------
<?php

set_time_limit(0); 
ini_set("memory_limit","-1");

$temp = str_repeat("ffkl2kfj\nflkdsjf \rflksdjfldskjLJFDSL djsk|fhgjk{}fkgkjfdk",10000000);
explode("|",$temp);

echo "ended";

?>

Expected result:
----------------
Memory should be released as soon the request was finished.

Actual result:
--------------
Memory is not being cleaned.