cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "sankalp kohli (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-10726) Read repair inserts should not be blocking
Date Tue, 15 Dec 2015 18:32:46 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-10726?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15058496#comment-15058496
] 

sankalp kohli commented on CASSANDRA-10726:
-------------------------------------------

cc [~brandon.williams] [~slebresne] 
What do you think? 

> Read repair inserts should not be blocking
> ------------------------------------------
>
>                 Key: CASSANDRA-10726
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10726
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Coordination
>            Reporter: Richard Low
>
> Today, if there’s a digest mismatch in a foreground read repair, the insert to update
out of date replicas is blocking. This means, if it fails, the read fails with a timeout.
If a node is dropping writes (maybe it is overloaded or the mutation stage is backed up for
some other reason), all reads to a replica set could fail. Further, replicas dropping writes
get more out of sync so will require more read repair.
> The comment on the code for why the writes are blocking is:
> {code}
> // wait for the repair writes to be acknowledged, to minimize impact on any replica that's
> // behind on writes in case the out-of-sync row is read multiple times in quick succession
> {code}
> but the bad side effect is that reads timeout. Either the writes should not be blocking
or we should return success for the read even if the write times out.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message