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.
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Manik Surtani
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