Description
Description
I'm using the Serializer component to deserialize objects with 100+ properties. In some cases, Symfony\Component\PropertyInfo\PropertyInfoCacheExtractor::extract ends up being called thousands of times. I'm using memcache as the backend and profiling locally, so my results are a "best case" without any network latency.
9310 calls to extract, total 128ms, and 1340 gets from memcache, for a total of 69ms
In most cases, I'm deserializing complete objects, where every property is populated with something. By saving all properties into a single cache item, once the cache is populated I'm seeing a significant improvement.
9310 calls to extract, total 54ms, and 7 gets from memcache, for a total of 3ms
That's a 42% improvement locally, and assuming 1ms in network latency for a cache reads the real-world performance could be much worse.
Here's the proof-of-concept code I've used for this:
private function extract($method, array $arguments)
{
try {
$serializedArguments = serialize($arguments);
} catch (\Exception $exception) {
// If arguments are not serializable, skip the cache
return \call_user_func_array(array($this->propertyInfoExtractor, $method), $arguments);
}
$key = rawurlencode($method);
if (array_key_exists($key, $this->arrayCache) && array_key_exists($serializedArguments, $this->arrayCache[$key])) {
return $this->arrayCache[$key][$serializedArguments];
}
$item = $this->cacheItemPool->getItem($key);
$data = $item->get();
if ($item->isHit()) {
$this->arrayCache[$key] = $data[$key];
if (array_key_exists($serializedArguments, $data[$key])) {
return $this->arrayCache[$key][$serializedArguments];
}
}
if (!$data) {
$data = [];
}
$value = \call_user_func_array(array($this->propertyInfoExtractor, $method), $arguments);
$data[$key][$serializedArguments] = $value;
$this->arrayCache[$key][$serializedArguments] = $value;
$item->set($data);
$this->cacheItemPool->save($item);
return $this->arrayCache[$key][$serializedArguments];
}Questions I have:
- Is optimizing for the "most properties will need to be extracted case" best?
- Are there commonly used cached backends where rewriting the same cache key like this will cause problems?
Depending on the above, I'd like to file a pull request either modifying the existing extract method or adding a new class with the different behaviour.
aside The fact that there's a static array cache needs to be documented. By default I added in a Drupal memory cache in a chain, and the class docs should call out that's not needed. Or, we should benchmark Doctrine / Drupal to see if the performance improvement documented at #16838 (comment) still holds.