cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Sylvain Lebresne (JIRA)" <j...@apache.org>
Subject [jira] Commented: (CASSANDRA-1909) normal replication shouldn't happen on counter CFs.
Date Mon, 03 Jan 2011 13:12:48 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-1909?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12976727#action_12976727
] 

Sylvain Lebresne commented on CASSANDRA-1909:
---------------------------------------------

For counters, normal replication doesn't work because the counter logic requires that we first
insert the update to a first, master, replica, before attempting any replication of this update
(involving a read in particular). So, unless I've missed something in the last 2 weeks, the
choice for counters is either R.O.W or no replication (in which case, you'll only replicate
on read repair or run-of-the-mill repair).

In #1546, I proposed a slightly different approach where we kinda do the repair-on-write as
part of the write (for now I refer you to the patch of #1546 for the details). The obvious
drawback is that you'll add a read to the read path. BUT, not only can it be kept optional
as R.O.W is, but more importantly it allows to restore a good part of the usual consistency
level guarantees (I say 'good part' because it still doesn't solve the problem of failed update
that you don't know if you should replay or not). And it's easy to make CL.ONE not wait on
the replication (and thus the read), so we would still have something along the line of what
the current R.O.W does.

Anyway, all this jibber jabber to say that I plan to work on this pretty soon, and if nobody
is opposed to my idea (?), this may supersed this issue.

> normal replication shouldn't happen on counter CFs.
> ---------------------------------------------------
>
>                 Key: CASSANDRA-1909
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1909
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Gary Dusbabek
>            Assignee: Kelvin Kakugawa
>             Fix For: 0.8
>
>


-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message