Metadata cache uses `ArrayAdapter` instead of APCu

[usu]

API Platform version(s) affected: 3.0.0

Description
3.0 uses ArrayAdapter as Metadata Cache. In 2.7 the default was to utilize APCu when it was installed.

Was this changed by purpose?

--> If yes, I couldn't find this documented. The docu still says:

If the Symfony Cache component is available (the default in the API Platform distribution), it automatically enables support for the best cache adapter available.

--> If no, I think the following commit introduced the issue:
c76720e

Or do I need to change any config on my side during 3.0 upgrade?

How to reproduce
Upgrade to 3.0
Check symfony profiler for cache hit rate, which is significantly lower than before, as no Metadata is cached between separate requests.

[emmanuelballery]

Hi!

registerCacheConfiguration in the ApiPlatformExtension is indeed breaking the main caching abilities of our apps.

core/src/Symfony/Bundle/DependencyInjection/ApiPlatformExtension.php

Lines 499 to 511 in c76720e

	private function registerCacheConfiguration(ContainerBuilder $container): void
	{
	if (!$container->hasParameter('kernel.debug') || !$container->getParameter('kernel.debug')) {
	$container->removeDefinition('api_platform.cache_warmer.cache_pool_clearer');
	}
	$container->register('api_platform.cache.metadata.property', ArrayAdapter::class);
	$container->register('api_platform.cache.metadata.resource', ArrayAdapter::class);
	$container->register('api_platform.cache.metadata.resource_collection', ArrayAdapter::class);
	$container->register('api_platform.cache.route_name_resolver', ArrayAdapter::class);
	$container->register('api_platform.cache.identifiers_extractor', ArrayAdapter::class);
	$container->register('api_platform.elasticsearch.cache.metadata.document', ArrayAdapter::class);
	}

In prod we lost the filesystem cache. ArrayAdapter is not enough. Removing those lines from ApiPlatformExtension is fixing this caching mecanism because config/metadata/resource.xml is referencing the cache.system (adapter.filesystem in prod).

core/src/Symfony/Bundle/Resources/config/metadata/resource.xml

Lines 65 to 67 in c76720e

	<service id="api_platform.cache.metadata.resource_collection" parent="cache.system" public="false">
	<tag name="cache.pool" />
	</service>

For big apps, dev is really slow, as each required metadata is created once for each request, adding seconds to the clock. Opening Swagger UI is not possible (well xdebug stops us at 30 secondes) and exporting the full openapi schema is... difficult.

@alanpoulain I'm really sorry to bother you. Since you worked on this, would you be king enough to take a look when you'll have the time and maybe guide us to help fix this.

Thank you!

[acirulis]

I have successfully migrated first project from 2.6 to 3.0 (Nice first impressions 👍) - however I immediately spotted significant drop in performance. Request, which took under 500ms now takes >1500ms on (ENV=dev, DEBUG=true) and also takes 400ms vs 200ms on (ENV=prod, DEBUG=false).
I am using Redis Cache adapter for Symfony, no changes in configuration between 2.6 and 3.0.

It seems that changes mentioned by @emmanuelballery - registerCacheConfiguration in the ApiPlatformExtension helps to bring back performance to normal.

[webda2l]

I have successfully migrated first project from 2.6 to 3.0 (Nice first impressions +1) - however I immediately spotted significant drop in performance. Request, which took under 500ms now takes >1500ms on (ENV=dev, DEBUG=true) and also takes 400ms vs 200ms on (ENV=prod, DEBUG=false). I am using Redis Cache adapter for Symfony, no changes in configuration between 2.6 and 3.0.

It seems that changes mentioned by @emmanuelballery - registerCacheConfiguration in the ApiPlatformExtension helps to bring back performance to normal.

In dev, https://symfony.com/blog/new-in-symfony-6-1-serializer-profiling come at cost but there is definitely a performance issue related to the cache with the 3.0.

[acirulis]

Oh nice, @webda2l - since I started project with 6.0, after upgrade to 6.1 Serializer Profiling was disabled by default. After your mention I enabled it & it will be great tool for debugging. Performance impact is minimal.

[emmanuelballery]

Meanwhile, you can avoid this performance issue by overriding api platform cache in your services.yaml:

services:
    api_platform.cache.metadata.property:
        parent: cache.system
        tags: [ cache.pool ]
    api_platform.cache.metadata.resource:
        parent: cache.system
        tags: [ cache.pool ]
    api_platform.cache.metadata.resource_collection:
        parent: cache.system
        tags: [ cache.pool ]
    api_platform.cache.route_name_resolver:
        parent: cache.system
        tags: [ cache.pool ]
    api_platform.cache.identifiers_extractor:
        parent: cache.system
        tags: [ cache.pool ]
    api_platform.elasticsearch.cache.metadata.document:
        parent: cache.system
        tags: [ cache.pool ]

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[Megumin42]

The service api_platform.metadata.property.identifier_metadata_factory which is suggested to be removed in 3.0 by a TODO comment (TODO: in 3.0 the serializer property metadata factory doesn't need the resource metadata anymore so these will be removed) has no cache associated with it.

After adding a simple array cache for this service the performance significantly improves when the metadata caches are rebuilt.

# Speeds up api-platform cache build substantially
# May have to be removed soon when api-platform removes these services
# see vendor/api-platform/core/src/Symfony/Bundle/Resources/config/metadata/property.xml:41
api_platform.cache.metadata.identifier:
    parent: cache.adapter.array
    tags: [ cache.pool ]
api_platform.metadata.property.identifier_metadata_factory.cached:
    class: ApiPlatform\Metadata\Property\Factory\CachedPropertyMetadataFactory
    decorates: api_platform.metadata.property.identifier_metadata_factory
    decoration_priority: 99
    arguments:
        - '@api_platform.cache.metadata.identifier'
        - '@api_platform.metadata.property.identifier_metadata_factory.cached.inner'

[soyuka]

Is there something I can do to help with this?