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https://issues.apache.org/jira/browse/IGNITE-2655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15308862#comment-15308862
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Dmitriy Setrakyan edited comment on IGNITE-2655 at 5/31/16 11:54 PM:
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[~dmagda] [~v.pyatkov]
Couple of comments:
# Can you please think over this signature for predicate? apply(int n, Node n,
List<Node> assigned)
# If predicate is called with empty list then primary node for this partition
is examined.
# Or we can assign primary always on our own and call predicate only for
backups (which I would prefer). If someone needs full control, then he always
have an opportunity to implement affinity function on his own.
As I side note I would say that we are trying to force our users to do some
programming. Does anyone have any idea on how to do this without code? How
about supporting simple string expressions based on node attributes and/or ip
addresses?
was (Author: yzhdanov):
[~dmagda] [~v.pyatkov]
Couple of comments:
# Can you please think over this signature for predicate? apply(int n, Node n,
List<Node> assigned)
# If predicate is called with empty list then primary node for this partition
is examined.
# Or we can assign primary always on our own and call predicate only for
backups (which I would prefer). If someone needs full control, then he always
have an opportunity to implement affinity function on his own.
As I side node I would say that we are trying to force our users to do some
programming. Does anyone have any idea on how to do this without code? How
about supporting simple string expressions based on node attributes and/or ip
addresses?
> AffinityFunction: primary and backup copies in different locations
> ------------------------------------------------------------------
>
> Key: IGNITE-2655
> URL: https://issues.apache.org/jira/browse/IGNITE-2655
> Project: Ignite
> Issue Type: Bug
> Reporter: Denis Magda
> Assignee: Vladislav Pyatkov
> Priority: Critical
> Labels: important
> Fix For: 1.7
>
>
> There is a use case when primary and backup copies have to be located in
> different racks, building, cities, etc.
> A simple scenario is the following. When nodes are started they will have
> either "rack1" or "rack2" value in their attributes list and we will enforce
> that the backups won't be selected among the nodes with the same attribute.
> It should be possible to filter out backups using IP addresses as well.
> Presently rendezvous and fair affinity function has {{backupFilter}} that
> will work perfectly for the scenario above but only for cases when number of
> backups for a cache is equal to 1.
> In case when the number of backups is bigger than one {{backupFilter}} will
> only guarantee that the primary is located in different location but will NOT
> guarantee that all the backups are spread out across different locations as
> well.
> So we need to provide an API that will allow to spread the primary and ALL
> backups copies across different locations.
> The proposal is to introduce {{AffinityBackupFilter}} with the following
> method
> {{AffinityBackupFilter.isAssignable(Node n, List<Node> assigned)}}
> Where n - potential backup to check, assigned - list of current partition
> holders, 1st is primary
> {{AffinityBackupFilter}} will be set using
> {{affinity.setAffinityBackupFilter}}.
> {{Affinity.setBackupFilter}} has to be deprecated.
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