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From Kanak Biscuitwala <kana...@hotmail.com>
Subject RE: Question about helix state transition
Date Sun, 01 Nov 2015 22:31:27 GMT
That shouldn't be possible. The sequence is: (1) ideal state change, (2) controller detects
change and sends messages, (3) each node applies messages, invokes the state transition handler,
and when the handler returns, updates its current state, (4) the controller sees the change
in current state and updates the external view.


The external view and ideal state may not always match, but the controller will send messages
to nodes such that the external view will eventually match within the constraints on the cluster.

From: hahn.jiang.pro@gmail.com
To: user@helix.apache.org
Subject: Question about helix state transition
Date: Thu, 29 Oct 2015 13:17:23 +0800

hi,
  I deploy a cluster with helix. When I start a instance, helix will change EXTERNALVIEW before
my service complete the transition function. is that right? I think helix can change EXTERNALVIEW
after my service complete transition function successfully. how can I configure my helix.

  Next, I have a question about helix source code. I found helix just update IDEALSTATES when
I call rebalance function. Then  helix send a message and this message tell the cluster changes
EXTERNALVIEW state to IDEALSTATES. Some time my cluster’s EXTERNALVIEW and IDEALSTATES are
not same. Does helix can know this difference and do something.

Thanks 		 	   		  
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