Explain memory_get_usage() in php

 

memory_get_usage() is a PHP function used to retrieve the amount of memory, in bytes, that is currently being allocated to the PHP script during its execution. This function can be valuable for monitoring and optimizing memory usage within your PHP application.

Here's a brief explanation of the memory_get_usage() function:

php
int memory_get_usage(bool $real_usage = false)

• Parameters:

  • $real_usage (optional): When set to true, the function returns the real system memory usage, which may be higher than the amount allocated to PHP. If set to false or omitted, it returns the memory usage within the PHP script.

• Return Value:

  • The function returns the memory usage in bytes as an integer.

Here's a simple example:

php
<?php


// Start memory usage

$start_memory = memory_get_usage();


// Allocate some memory

$data = str_repeat('a', 1024 * 1024); 
// Allocating 1 MB of memory


// Get current memory usage

$current_memory = memory_get_usage();


// Output memory usage

echo "Memory usage before: " . $start_memory . " bytes\n";

echo "Memory usage after: " . $current_memory . " bytes\n";

echo "Memory usage diff: " . ($current_memory - $start_memory) . " bytes\n";


?>

In this example, the memory_get_usage() function is used to measure the memory usage before and after allocating a block of memory with str_repeat. The difference between the two memory measurements represents the amount of memory used by the script during the allocation.

Keep in mind that the actual memory usage can be influenced by various factors, and interpreting the results may require consideration of PHP's memory management mechanisms. Additionally, it's worth noting that the memory_get_usage() function provides a snapshot of the memory usage at the moment it's called and may not represent the peak usage during the script's execution. For peak memory usage, you can use memory_get_peak_usage().