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From "Alex Petrov (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (CASSANDRA-7581) Stop read requests for partitions which don't belong to a node
Date Wed, 11 May 2016 07:30:13 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-7581?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15278153#comment-15278153
] 

Alex Petrov edited comment on CASSANDRA-7581 at 5/11/16 7:29 AM:
-----------------------------------------------------------------

This issue looks related to [7592|https://issues.apache.org/jira/browse/CASSANDRA-7592], although
7592 seems to have a more complete scope description. Although suggested solution might solve
both issues: by dropping read requests coordinator will be able to pick another node to read
from.

-This problem seems not to apply to local mutations, as they're always checked for {{appliesLocally}}.
So in the end it might be a good idea to have similar flow for reads.-

I've checked the code in more detail. At the moment both mutations and read commands are applied
without additional checks for token endpoints. It can be done quite simply via the {{StorageService}}.

But in general, replica may have an incorrect view of the ring, just as coordinator can. Although
if the replica has the wrong view, it would be better if it doesn't serve requests.


was (Author: ifesdjeen):
This issue looks related to [7592|https://issues.apache.org/jira/browse/CASSANDRA-7592], although
7592 seems to have a more complete scope description. Although suggested solution might solve
both issues: by dropping read requests coordinator will be able to pick another node to read
from.

This problem seems not to apply to local mutations, as they're always checked for {{appliesLocally}}.
So in the end it might be a good idea to have similar flow for reads.

> Stop read requests for partitions which don't belong to a node
> --------------------------------------------------------------
>
>                 Key: CASSANDRA-7581
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7581
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: sankalp kohli
>            Assignee: Alex Petrov
>            Priority: Minor
>
> A C* instance will serve CF level reads with null values or old values to a co-ordinator
even if the instance is not responsible for the data. 
> This is bad if co-ordinator has a wrong view of the ring and will return wrong results
back to the client. 
> A solution to this problem could be to not respond or return error to such read requests.

> Tricky part here is to respond to read requests when the instance has just lost ownership
for a few ring delay. 
>  



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