[infinispan-dev] Let me understand DIST

[Bela Ban]

On 3/15/12 4:25 PM, Manik Surtani wrote:
>
> On 15 Mar 2012, at 04:31, Bela Ban wrote:
>
>> If we touch a lot of keys, then sending *all* of the keys to all owners
>> may be sub-optimal; as an optimization, we may want to send only the
>> keys to the nodes which need to store them. This would make the PREPARES
>> potentially much smaller.
>
>
> Not really - if we are sending different prepares to different nodes (containing different writes) then the serialisation overhead goes up since each recipient gets a different byte buffer.  In the current case we reuse the byte buffer.


In my experience, serialization is never the bottleneck, it is 
*de-serialization*, so this shouldn't be a problem. Also, I don't see 
why serialization of keys [1..9] shouldn't take roughly the same time as 
serialization of keys [1..3], [4..6], [7..9].

If we have a TX which touches a lot of keys, unless we break the key set 
down into their associated targets, we would have to potentially 
transfer a *big* state !


-- 
Bela Ban, JGroups lead (http://www.jgroups.org)