[infinispan-dev] Cache Java 8 API proposal - 2nd draft

[Dan Berindei]

On Mon, Jun 8, 2015 at 10:37 AM, Galder Zamarreño <galder at redhat.com> wrote:
>
>> On 5 Jun 2015, at 14:15, Radim Vansa <rvansa at redhat.com> wrote:
>>
>> Is the marshalling comparison really fair? The lambda-table-based
>> approach removes the need for serializing the class definition, but in
>> practice - is the class definition always send around with each RPC?
>
> ^ We've extensively added Infinispan Externalizers (which use the Object Table approach shown in MarshallingTests) to reduce the size of our payloads, and indeed for all those, no class definitions are sent around. So, as long as the types of those are known to us, we can use such approach and avoid expensive serialization.
>
> NOTE: JBoss Marshalling's Externalizers are more expensive than ObjectTable based approach but I can't remember why, it might be cos when you use those, it might send the externalizer class' class definition around, but not sure.


I think the Simple/DynamicClassTable classes in WildFly take care of
writing only a class id in the stream, instead of the class name, same
as our ExternalizerTable but using JBoss Marshalling's Externalizers.
I don't know if there's any performance difference between the two
approaches, but I assume they must be pretty similar.

>
>> If
>> it is so, it seems like a serious flaw of the current codebase, and not
>> something occurring only for the functional interface. In case that we
>> keep the marshallers around, we should marshall second RPC (with the
>> same lambda and another instance of the same captured class), and look
>> on the diff rather than on the first serialized instance.
>
> ^ Hmmm, not sure what you mean there exactly.
>
>>
>> Radim
>>
>> On 06/05/2015 11:44 AM, Galder Zamarreño wrote:
>>> Hi all,
>>>
>>> Thanks to all who contributed to the 1st draft revision. We've taken all that input and created a separate Github project where we have prototytped the 2nd draft of the advanced Java 8 based Infinispan API. The starting point for you should be FunctionalMap [1].
>>>
>>> Here's a brief summary the major changes since the 1st draft:
>>>
>>> 1. FunctionalMap has been separated into 3 sub-interfaces, one for read only operations, one for write only operations, and a final one for read-write operations. This separation makes it clear the purpouse of each operation and adds a nice layer of type safety, e.g. you can't write with a read-only map, or you can't read with a write-only map.
>>>
>>> 2. Param has been added, which is equivalent to Infinispan Flag with the added benefit that it can carry values. There's no such example right now but we could have in the future.
>>>
>>> 3. MetaParam has been added. This is a much more flexible and extensible option compared to the current Infinispan's Metadata.
>>>
>>> 4. For operations returning mutiple returns, or working on multiple elements, we've exposed something called Traversable, which is a subset of Java's Stream. See its javadoc to find out more. Kudos to Will for his work on distributed streams which has helped hugely with the design of Traversable.
>>>
>>> 5. Listeners have been added, again separating between read-write and write-only listeners (JCache does not offer read-only listeners, e.g. cache entry visited, and hence I think we'll drop our cache entry visited listener at some point).
>>>
>>> 6. Will and I have explored marshalling aspects of lambdas, and there are some interesting ways to reduce their costs by +90%! See MarshallingTest for different options to marshall both capturing and non-capturing lambdas and their cost in terms of payload sizes.
>>>
>>> Some final notes:
>>>
>>> * Please do read the javadocs, they contain a lot of information on the reasons behind the design.
>>>
>>> * To find out how the different functional map variants are used, look at ConcurrentMapDecorator and JCacheDecorator who use them to implement the ConcurrentMap and javax.cache.Cache APIs respectively.
>>>
>>> * FunctionalMapTest contains examples on how to use functional map variants for other operations which we deeply care about, e.g. Hot Rod atomic version-based replace function.
>>>
>>> Special thanks to Mario Fusco (Java 8 In Action book co-author) for his feedback throughout this 2nd draft design process.
>>>
>>> Cheers,
>>>
>>> [1] https://github.com/infinispan/proto8/blob/master/src/main/java/org/infinispan/api/v8/FunctionalMap.java
>>> --
>>> Galder Zamarreño
>>> galder at redhat.com
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> infinispan-dev mailing list
>>> infinispan-dev at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>
>>
>> --
>> Radim Vansa <rvansa at redhat.com>
>> JBoss Performance Team
>>
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>
>
> --
> Galder Zamarreño
> galder at redhat.com
>
>
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