[
https://issues.apache.org/jira/browse/CASSANDRA-11488?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15225928#comment-15225928
]
Sylvain Lebresne commented on CASSANDRA-11488:
----------------------------------------------
I'm not sure there is a clearly _right_ answer here. The historical reason why
{{SimpleSnitch}} doesn't sort is for a use where people want to ensure all
reads (at CL.ONE) for a given were hitting the same replica to optimize row
cache usage. That is, this use case is trying to have a partition loaded in the
row cache on only one replica (even if RF>1 that is), and so no reading locally
if you likely don't have the partition in cache is actually what is wanted.
That's the historical reason, but with that said:
* I have no clue how many people use this. Especially since the snitch is
configured cluster wide. I could see this property be useful on a very specific
table, but not for a cluster in general.
* We don't advise disabling the dynamic snitch (we don't even show the
disabling option in the default configuration at all) pretty much ever. Which
should make whether {{SimpleSnitch}} sorts or not largely irrelevant.
Overall, I don't think the absence of sorting matters much in practice (due to
the dynamic snitch) and it _might_ be relied on by a handful of users. It has
also been like that forever without much concrete user complaints. So I'd lean
toward leaving things be, though maybe there is some improvement in documenting
this to be made.
> Bug or not?: coordinator using SimpleSnitch may query other nodes for copies
> of local data
> -------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-11488
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11488
> Project: Cassandra
> Issue Type: Bug
> Reporter: Jim Witschey
> Assignee: Stefania
> Priority: Minor
>
> As [~Stefania] explains [in this JIRA
> comment|https://issues.apache.org/jira/browse/CASSANDRA-11225?focusedCommentId=15221059&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15221059],
> {{SimpleSnitch}} does not implement
> {{IEndpointSnitch.sortByProximity(localhost, liveendpoints)}}, so a query for
> data on the coordinator may query other nodes. That seems like unnecessary
> work to me, and on that note, Stefania woonders [in this JIRA
> comment|https://issues.apache.org/jira/browse/CASSANDRA-11225?focusedCommentId=15223598&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15223598]
> - should this be considered a bug?
> Stefania, I'm assigning you here -- could you find the right people to
> involve in this discussion?
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
