[infinispan-dev] Re: JProfiler snapshots for Infinispan+JBMAR

[Bela Ban]

David M. Lloyd wrote:
> Yes, Galder has such a test. :-)  And yes, JBoss Marshalling writes 
> booleans as a single byte

Do you encode the value and type into the single byte ? Assuming you 
need 1 bit for the value, you have 7 bits left for the type, which 
leaves you with ~ 128 types. Is this assumption correct ?


> (or, in the case of boolean[], a single bit).

How ?



> The test won't likely pass fully until Galder reimplements the custom 
> marshalling parts as ObjectTable instead of Externalizers.  With the 
> current Externalizer-based design, it might write:
>
>   - This is an externalized object = 1 byte
>   - The class of the externalized object is in the class table = 1 byte
>   - The class table entry for the externalized class = 1 byte
>   - The externalizer object is predefined = 1 byte
>   - This is the custom ID of the externalizer object = 1 byte
>   - Begin custom object data = 1 byte
>   - Custom object data length = 1-4 bytes depending on N
>   - This is the custom object data = N bytes
>   - End custom data = 1 byte
>
> Giving 8+N to 11+N bytes or more, depending on the mix of objects and 
> primitive data in the custom data block, due to the security features 
> in Externalizers which are not needed in ISPN.  With an object table 
> it would write:
>
>   - This object is predefined = 1 byte
>   - This is the custom ID of the predefined object = 1 byte
>   - This is the custom object data = N bytes

This is 3 bytes compared to the 2 currently used, and - as you said 
above - I think we can even get down to only 1 byte for a boolean (or 
Boolean). I don't want to nitpick, but can't we get JBMAR to marshall a 
boolean into 1 byte ? If we send 10 million messages with a boolean, 
then the overhead gets quite large !


-- 
Bela Ban
Lead JGroups / Clustering Team
JBoss - a division of Red Hat