Explain memory_get_peak_usage() in php

 

The memory_get_peak_usage() function in PHP is used to retrieve the peak memory usage, in bytes, that occurred during the execution of a script. This function provides information about the maximum amount of memory allocated to a PHP script since the script started running.

Here's a breakdown of the memory_get_peak_usage() function:

php
int memory_get_peak_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 peak memory usage in bytes as an integer.

Here's a simple example demonstrating the use of memory_get_peak_usage():

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 peak memory usage

$peak_memory = memory_get_peak_usage();


// Output peak memory usage

echo "Peak memory usage: " . $peak_memory . " bytes\n";


?>

In this example, the script starts by measuring the initial memory usage using memory_get_usage(). After allocating a block of memory with str_repeat, it then uses memory_get_peak_usage() to retrieve the peak memory usage. The output will display the maximum amount of memory that the script consumed during its execution.

The $real_usage parameter can be set to true to get the real system memory usage, which may include memory used by other processes. However, keep in mind that the "real" memory usage may not be available on all systems and may require specific PHP configurations.

This function is valuable for profiling and optimizing your PHP scripts, allowing you to identify and address potential memory issues.