Example of memory_get_usage getting the current PHP memory consumption

? & Lt;? Php

 ?>



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Output: 62328 122504 62416
Note: The value output by the memory_get_usage() function is in bytes

function convert($size){

$unit=array('b','kb','mb','gb','tb','pb');

?>



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Output: 256 kb

3. Custom function to obtain the size of array or variable value
 function array_size($arr) { ob_start(); $mem = preg_replace(" /n +/", "", $mem);
$mem = strlen($mem);
return $mem;
}
$memEstimate = array_size($GLOBALS);
?>


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Instructions:
To reduce memory usage, you can use the PHP unset() function to delete variables that are no longer needed.
Similar functions: PHP mysql_free_result() function can clear the result set obtained by querying the database that is no longer needed, so that more available memory can be obtained.

PHP memory_get_usage() can also have a parameter, $real_usage, whose value is a Boolean value. The default is FALSE, which means that the obtained memory usage does not include the memory occupied by this function (PHP memory manager);
When set to TRUE, the resulting memory includes the memory occupied by this function (PHP memory manager). 
In PHP programming, you can use PHP memory_get_usage() to compare the memory occupied by each method, and then choose the method with better performance.