Re: [infinispan-dev] Rehashing on view changes
On 11/26/10 2:59 PM, Vladimir Blagojevic wrote:
On 10-11-26 10:50 AM, Bela Ban wrote:
> Quick question: when I have a view {A,B,C,D,E,F} at time T and then
> receive 2 subsequent views within 3 seconds:
>
> - {A,B,C}
> - {A,B,C,E,F}
>
> will there be 2 rehashes / rebalancings, or 1 ? Is there a delay that
> can be configured for rebalancing on view changes ?
2 rehashes.
OK, good to know. I'll add some code to RELAY which hides the first view
{A,B,C} and installs {A,B,C,E,F} directly. Unless, of course, D, E and F
have failed, then {A,B,C} *will* get installed.
The simple solution I have in mind is to wait a little before removing
all of the remote nodes when D crashes. The wait of course onyl needs to
happen when we know we have more than 1 node in the remote cluster. This
is essentially optimistically assuming that E will take over, and won't
help on a network partition.
Once ISPN-493 is done, I can remove that code again.
That idea about delay in initiating rehash is excellent! However, we
have to be careful to include delay only for high view instability. This
is actually on my plate https://jira.jboss.org/browse/ISPN-493
OK. I think the delay should be configurable (0 turns it off)...
--
Bela Ban
Lead JGroups / Clustering Team
JBoss