[infinispan-dev] Stream encoding of Flags and future compatibility

[Galder Zamarreño]

On May 11, 2012, at 6:23 PM, Sanne Grinovero wrote:

> On 11 May 2012 16:37, Galder Zamarreño <galder at redhat.com> wrote:
>> Quickly tried this and caused no issues:
>> https://github.com/galderz/infinispan/commit/7718926e5a4a6763506250362d7bd5cbdccd2931
> 
> Looks good! I'm sure this doesn't solve all future migration problems,
> but if we could keep this kind of tricks around it should improve
> odds.
> IMHO, this is a kind of sensitivity that we should apply across all
> areas (not just flags).

^ I agree. I'm working on https://issues.jboss.org/browse/ISPN-2034 which should highligh this kind of issues.

> 
> On a totally different page, why are we serializing Flags one-by-one ?
> We mostly need to serialize EnumSets right?
> An EnumSet can be encoded by using the bits of a couple of bytes.
> Three bytes looks like enough for all our needs.. we could even be
> clever and reserve a special Externalizer-ID for the empty set, to
> avoid 3 bytes where none are needed.
> While currently we need an integer (4 bytes) to encode the header for
> "EnumSet", plus (4 bytes header + 1 byte value) * each flag -> a lot.

Makes sense. We already do a similar thing for Hot Rod flags. Can you add a jira for it and assign it to me?

> 
>> 
>> On May 9, 2012, at 2:56 PM, Sanne Grinovero wrote:
>> 
>>> I'm having an interesting "chat" with Galder on github after a pull request:
>>> https://github.com/galderz/infinispan/commit/74b065d4f520d4a22dfa6ef78ae80e7aa19621d3#commitcomment-1310043
>>> 
>>> The pull request itself was resolved, but we ended up brainstorming
>>> about how we should encode some objects (Flags in this case) to make
>>> sure we don't make it highly unlikely to be able to support rolling
>>> upgrades in the future.. which is something we really have to think
>>> about today imho.
>>> 
>>> Cheers,
>>> Sanne
>>> _______________________________________________
>>> infinispan-dev mailing list
>>> infinispan-dev at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>> 
>> --
>> Galder Zamarreño
>> Sr. Software Engineer
>> Infinispan, JBoss Cache
>> 
>> 
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> 
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--
Galder Zamarreño
Sr. Software Engineer
Infinispan, JBoss Cache