[infinispan-dev] [ISPN-731] - make rehashing state and tx log draining serial

[Manik Surtani]

On 10 Nov 2010, at 13:09, Vladimir Blagojevic wrote:

> 
> On 2010-11-08, at 9:01 AM, Mircea Markus wrote:
> 
>>>> 
>>> 
>>> Shouldn't you count down after receivers have applied the state, and have then ack'd that this state has been applied?  Rather than when the state has been picked up?
>>> 
>>>> State provider awaits on a latch for a 
>>>> given view id and a timeout. When await returns it drains the tx log.
>>> 
>>> Rather than a countdown latch, wouldn't you rather maintain a synchronized set or something with the addresses of the recipients, and you only proceed when this set is empty?  Tighter control rather than a simple countdown.
>>> 
>>> Also, how do you plan on dealing with exceptional circumstances, e.g., a receiver node crashing before sending this ack?  Would that not block the entire rehash process?  Or would the node crashing cause a new view change, which will abort the LeaveTask (interrupt) and cause it to start all over again?
>> +1 that's something we should be prepared for.
>> That makes me think about an more interesting problem as well: what happens when a node crashes in the middle of tx log draining? Not sure the tx log can revert itself to the initial state, can it? Again something we should look into. 
> 
> Ok, both of you convinced me. I have a working solution for ISPN-731. There are so many if scenarios with rehashing that they should be dealt with separately and thoroughly. What do you say I amend ISPN-493 with your comments above and we make the fix version 4.2 CR2 as well?

We can wait for this for CR1, even.  How long do you reckon you need?

--
Manik Surtani
manik at jboss.org
Lead, Infinispan
Lead, JBoss Cache
http://www.infinispan.org
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