[TYPO3-core] [OT] Could not acquire lock for ClassLoader cache creation

[Peter Russ]

--- Original Nachricht ---
Absender: Markus Klein
Datum: 08.05.2014 11:49:
> Hi Peter!
>
>> Thank you for your reply, Markus.
>> Most interesting part for me: "we invested quite some time to find a safe
>> default".
>> This means: not enterprise ready ;-)
> What has a safe default to do with enterprise readiness??
So far there is no way to implement and use own locking. As mentioned 
below is target for 6.3 LTS.
>
>> It should be configurable like the caching framework: default locker is file
>> locking. But there could also be DB based, APC or memcache based lockers.
> ClassLoader uses the normal caching framework. But locking has nothing to do with the caching framework. Synchronization (and therefore locking) has to take place before you access the cache.
> The reason to fix the synchronization for the ClassLoader cache accesses to file locking is that it provides a basic synchronization mechanism for concurrent requests. No other Core supported locking mechanism provides a synchronization mechanism (see Locker::isLocked()), hence you need to build it around the locking method. And this is where the problem  begins - as written above - there's no safe, generic way to do that with PHP.

I never mentioned classloader nor compared locking with caching 
framework: "should be configurable like" ;-)

>> That's what I would expect from a solution claiming "enterprise" cms.
>> But definetly not "by default in most cases".
>>
>> If help is required pls let me know.
> For 6.3 we want to rewrite the Locker class such that you can extend it with your own locker implementations.
> We still would love to see a good and widely working synchronization mechanism for all TYPO3 CMs caches. Either a layer in front of the cache frontends or - and more likely this will be the case - an implementation of synchronization in all places where caches are used.
> You can take a look at http://wiki.typo3.org/Blueprints/LockingForCaches where I explain our current situation.
>

Excellent blueprint.


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