[wildfly-dev] SimpleRoleGroup#roles

[David M. Lloyd]

You don't have to break the serialized form to make this kind of change. 
  Have a look at this: 
https://docs.oracle.com/javase/7/docs/platform/serialization/spec/serial-arch.html#6250

Set that up, plus a customized readObject()/writeObject(), and you can 
retain serialization compatibility.

On 06/09/2015 12:37 AM, Philippe Marschall wrote:
> Very well, we can do that. How do you feel about breaking the serialized
> form?
>
>
> On 08.06.2015 15:20, Stefan Guilhen wrote:
>> The order of the roles is not important. I think we should change the
>> SimpleRole implementation in PicketBox to use Collection (HashSet)
>> reference instead of List and then change any WildFly code that might be
>> using the List reference.
>>
>> On 06/08/2015 03:25 AM, Philippe Marschall wrote:
>>> Hi
>>>
>>> I’m aware this may no technically be the right list to discuss this
>>> but this list is impacted by this and fairly active.
>>>
>>> During load testing of our application we found a case we spend 10% of
>>> your CPU time in SimpleRole#equals (see attachment). This is because
>>> SimpleRoleGroup uses an ArrayList to maintain a unique set of roles.
>>> As a result it has to call ArrayList#contains a lot, which is itself
>>> O(n). In fact because that’s done when iterating over all the roles it
>>> becomes O(n^2). In our case our principals can have up to 200 roles. I
>>> don’t know if this is exceptionally many or a common case.
>>>
>>> We would like to work on a patch but we need your guidance. There are
>>> several possible solutions and it all comes down to whether we can
>>> change the List in the RoleGroup interface to a Collection. All the
>>> users we searched for in WildFly only used the return value for
>>> iterating over, nobody used the index. In fact they all used it an a
>>> for-each loop so the change would even be source compatible but
>>> unfortunately not binary compatible. If we can change the interface
>>> then we can just change the ArrayList in SimpleRoleGroup to a HashSet
>>> and be done with it. If the order is important the we can either use a
>>> TreeSet or a LinkedHashSet.
>>> If changing the RoleGroup interface is not possible then there are two
>>> other possibilities. The first is only internally using a Set but in
>>> getRoles perform a copy. This would produce more garbage. The second
>>> option would be a having a Set and List (to avoid having to do copies)
>>> in SimpleRoleGroup. This would avoid having to do a copy and the Set
>>> can be used for contains checks. Only removeRole would still be O(n)
>>> due to the scan over ArrayList. The only user we found was
>>> OptionsRoleMappingProvider.
>>> All of these would change the serialized form. If it is important to
>>> support reading old instances that could be added as well.
>>>
>>> Cheers
>>> Philippe
>>>
>>>
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>>> https://lists.jboss.org/mailman/listinfo/wildfly-dev
>>
>>
>>
>>
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