Modern PHP 8.x & Internals
10+ Years (Principal / Architect)
Hard
Production Scenario
How do you design a High-Performance In-Memory Cache using Shared Memory (`shmop` / APCu) in PHP without Redis?
Real-World Scenario / Incident Description
A microservice running on a single bare-metal server needs to read configuration maps in sub-0.1ms without network socket overhead.
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Updated 1 month ago
APCu Direct RAM Access
APCu stores PHP variables directly in the web server process shared memory, avoiding TCP network roundtrips to Redis:
if (! apcu_exists('global_config')) {
$config = loadHeavyConfig();
apcu_store('global_config', $config, 3600);
} else {
$config = apcu_fetch('global_config');
}
Latency is under 5 microseconds, compared to 0.5-2ms for Redis over TCP.
Related Concepts:
#APCu
#Shared Memory
#Low Latency
#Cache
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