[infinispan-dev] Ideas for locking improvements

[Manik Surtani]

On 18 May 2011, at 13:32, Sanne Grinovero wrote:

>> 5.  This sounds good, except that doesn't a lock coordinator failing result in a network storm of each and every node in the cluster which had 1 or more locks on the lock coordinator now pinging the new lock coordinator with a message?  I presume these can be compacted into a single RPC per node, but still ...
> 
> If a single key is involved, obviously not more than one node. When
> multiple keys are involved, then each owner would want to ping the new
> key owner; but if a single node crashed, isn't it the case that the
> ownership of these locks is all moved to only two nodes, the next and
> previous on the wheel ? So basically the nodes having a lock would
> aggregate one RPC each to ~2 nodes.

Yes.  So in a cluster of N nodes, on node failure, you trigger 2 x (N-2) unicasts.

> Also the amount of network traffic is
> -  less than whatever traffic would be caused to re-acquire the same
> locks & values to retry the transaction, which would likely happen in
> case we did not apply these optimisations

True.


--
Manik Surtani
manik at jboss.org
twitter.com/maniksurtani

Lead, Infinispan
http://www.infinispan.org