SIMPLE PHP MEMORY MANAGEMENT TIPS

quick guide & examples

PHP MYSQL

CURRENT MEMORY USAGE (BYTES) echo memory_get_usage();

CHECK MEMORY USAGE

01

PEAK MEMORY USAGE (BYTES) echo memory_get_peak_usage();

CONNECT TO DATABASE $pdo = new PDO("mysql:host=HOST; dbname=NAME;charset=utf8mb4", USER, PASSWORD); 

DATABASE FETCH LINE BY LINE

02

PREPARE SQL $stmt = $pdo->prepare("SELECT * FROM `TABLE`"); $stmt->execute();

BAD - FETCH ALL AT ONCE $r = $stmt->fetchAll();

GOOD - FETCH LINE-BY-LINE while ($r = $stmt->fetch()) { print_r($r); }

READ FILE LINE BY LINE

03

BAD - READ EVERYTHING INTO A STRING $contents = file_get_contents("FILE");

GOOD - READ LINE BY LINE $fh = fopen("FILE", "r"); while ($line = fgets($fh)) { echo $line; } fclose($fh);

REDUCE VARIABLES

04

BAD - NEEDLESS VARIABLES $varA = 123; $varB = 234; $varC = $varA + $varB;

GOOD - NO EXTRA VARIABLES $varC = 123 + 234;

MANUAL REMOVE VARIABLES

05

TEMPORARY VARIABLES $varA = 123; $varB = 234; $varC = $varA + $varB;

REMOVE IF NO LONGER IN USE unset($varA); unset($varB); gc_collect_cycles();