[
https://issues.apache.org/jira/browse/IGNITE-4501?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15972575#comment-15972575
]
Alexander Menshikov commented on IGNITE-4501:
---------------------------------------------
[~yzhdanov],
And one new case can happen. When message reaches the coordinator, and the
coordinator sends it to next node, and the coordinator crashes after that, and
some node in the middle are becoming a new coordinator, and message will reach
this new coordinator, after that all nodes after new coordinator will not see
the added message.
It can happen because candidates for coordinators sorted in the ring in the
different order than nodes.
> Improvement of connection in a cluster of new node
> --------------------------------------------------
>
> Key: IGNITE-4501
> URL: https://issues.apache.org/jira/browse/IGNITE-4501
> Project: Ignite
> Issue Type: Improvement
> Components: messaging
> Affects Versions: 1.8
> Reporter: Vyacheslav Daradur
> Assignee: Alexander Menshikov
> Fix For: 2.0
>
>
> h3. Main description:
> Cluster nodes connect a ring.
> For example: we have 6 nodes: A, B, C, D, E, F.
> They can connect a ring in any possible way: A-B-C-D-E-F-A, or A-F-B-E-C-D-A,
> etc.
> If some node leaves topology, adjacent nodes must reconnect.
> If nodes A, B, C are in same physical place, nodes D, E, F are in other
> place, and places lost connect each other, we will have many ways of
> reconnections.
> At best case, if we had a ring: A-B-CxD-E-FxA ('x' means disconnect) -- then
> we have only one reconnect (C
> will be connected to A or F will be connected to D -- depends on what part of
> the cluster was alive.
> Also, if we had a not ring: AxFxBxExCxDxA -- then we have a lot of
> reconnections (A to B, B to C, C to A -- in general n/2 reconnections, where
> n -- number of nodes).
> h3. Approach:
> It is necessary to develop approach of node insertion to the correct place
> for creation of the correct ring-topology.
> h3. Solutions:
> Main idea is a sorting according to latency.
> * group nodes in arcs on an ARC_ID. (manualy?)
> * implement NodeComparator (nodes on the same host : nodes on the same subnet
> : other nodes). We will use it when we connect a new node.
> * [dev list
> thread|http://mail-archives.apache.org/mod_mbox/ignite-dev/201612.mbox/%3CCAN+WSNyWYXSXEBpGErVt72zTgi2pTQzUWLv8JY=ke83-5-r...@mail.gmail.com%3E]
> Update Dec, 29 Yakov Zhdanov:
> # introduce CLUSTER_REGION_ID node attribute. This can be done by adding
> public static final constant to TcpDiscoverySpi.
> # Alter
> org.apache.ignite.spi.discovery.tcp.internal.TcpDiscoveryNodesRing#nextNode(java.util.Collection<org.apache.ignite.spi.discovery.tcp.internal.TcpDiscoveryNode>)
> to order basing on per node attribute value
> # Node comparison should be stable and consistent. E.g. if CLUSTER_REGION_IDs
> are equal then we should compare nodes' IDs. This way we have consistent
> order on all nodes in topology.
> # Also nextNode() has to group nodes on same host and in same subnet. This
> can be postponed and implemented after we have other points done.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
