PHP Performance Tips: Write Faster PHP Code

What is it?

PHP application performance comes down to a small number of high-impact areas: bytecode caching with OpCache, eliminating redundant database queries, and caching expensive results. These optimisations can make a slow app 10x faster.

Why does it matter?

Slow PHP costs money — server bills increase with load, and users abandon sites that take more than 2 seconds. Most performance problems trace back to a handful of well-known issues with well-known fixes.

PHP performance — OpCache, fixing N+1 queries, APCu caching, and profiling with Xdebug.

Real-World Use Cases

🔥 High-traffic product pages - Enable OpCache and cache the product list in APCu — serve thousands of requests without hitting the database every time.
🗄️ Dashboard with multiple queries - Fix N+1 by rewriting nested loops into a single JOIN query — reduce 101 queries to 1.
📧 Bulk email campaigns - Batch-process 10,000 emails using a while loop with fetch() instead of loading all rows into memory at once.
📊 Report generation - Cache expensive aggregate queries in Redis/APCu for 5 minutes — no need to SUM millions of rows on every page load.

Enable OpCache — Instant 2-10x Speedup

php.ini

opcache.enable=1
opcache.memory_consumption=256
opcache.interned_strings_buffer=16
opcache.max_accelerated_files=20000
opcache.validate_timestamps=1
opcache.revalidate_freq=60

Restart Apache/PHP-FPM.

Check:

<?php
var_dump(opcache_get_status());

Fix N+1 Queries — The Biggest Win

❌ Bad:

$users = $db->query("SELECT * FROM users");

foreach ($users as $user) {
    $orders = $db->query("SELECT * FROM orders WHERE user_id={$user['id']}");
}

✅ Good:

SELECT u.*, o.*
FROM users u
LEFT JOIN orders o ON o.user_id = u.id;

APCu Caching — Avoid Repeated DB Calls

$key = 'settings';

$data = apcu_fetch($key);

if ($data === false) {
    $data = $db->query("SELECT * FROM settings")->fetchAll();
    apcu_store($key, $data, 3600);
}

Clear cache:

apcu_clear_cache();

Performance priority

Fix N+1 queries ⭐⭐⭐⭐⭐
Add proper DB indexes ⭐⭐⭐⭐⭐
Enable OPcache ⭐⭐⭐⭐
APCu caching ⭐⭐⭐⭐
Redis for shared cache/sessions ⭐⭐⭐⭐
CDN for static files ⭐⭐⭐

Usually, fixing N+1 queries and enabling OPcache gives the largest immediate improvement.

Q: What is the single biggest PHP performance win?

Enabling OpCache. It makes PHP 2-10x faster with zero code changes. The second biggest win is fixing N+1 database queries with JOINs. Use EXPLAIN in MySQL to identify slow queries and add indexes.

Quick Access

Enable OpCache — Instant 2-10x Speedup

Fix N+1 Queries — The Biggest Win

APCu Caching — Avoid Repeated DB Calls

Performance priority

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