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Posted to commits@cassandra.apache.org by "Richard Low (JIRA)" <ji...@apache.org> on 2014/07/22 23:56:40 UTC

[jira] [Commented] (CASSANDRA-5901) Bootstrap should also make the data consistent on the new node

    [ https://issues.apache.org/jira/browse/CASSANDRA-5901?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14070988#comment-14070988 ] 

Richard Low commented on CASSANDRA-5901:
----------------------------------------

In particular, host replacement can violate consistency, even with CASSANDRA-2434. For example, if you always do quorum reads and writes and have replicas A, B, C, you'll always read the latest value, even if any one replica has missed a write. Suppose A did miss a write and then B fails and is replaced by D. D chooses where to stream from - there is no 'right' answer - so it can stream from A. Now A and D have old values and only C has the latest value. A quorum read that chooses A and D will give back stale data and violate expected consistency.

If a repair was run on A and C after B had failed but before it was replaced with D, the consistency problem is eliminated.

> Bootstrap should also make the data consistent on the new node
> --------------------------------------------------------------
>
>                 Key: CASSANDRA-5901
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5901
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: sankalp kohli
>            Priority: Minor
>
> Currently when we are bootstrapping a new node, it might bootstrap from a node which does not have most upto date data. Because of this, we need to run a repair after that.
> Most people will always run the repair so it would help if we can provide a parameter to bootstrap to run the repair once the bootstrap has finished. 
> It can also stop the node from responding to reads till repair has finished. This could be another param as well. 



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