cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jeremiah Jordan (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-7731) Get max values for live/tombstone cells per slice
Date Sat, 27 Sep 2014 23:12:34 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-7731?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14150805#comment-14150805
] 

Jeremiah Jordan commented on CASSANDRA-7731:
--------------------------------------------

This ticket is about displaying the max value reported by metrics in nodetool. Not about the
calculation of that value. Changing how the metrics themselves work is to be done in other
tickets previously mentioned.

> Get max values for live/tombstone cells per slice
> -------------------------------------------------
>
>                 Key: CASSANDRA-7731
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7731
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Cyril Scetbon
>            Assignee: Robert Stupp
>            Priority: Minor
>             Fix For: 2.1.1
>
>         Attachments: 7731-2.0.txt, 7731-2.1.txt
>
>
> I think you should not say that slice statistics are valid for the [last five minutes
|https://github.com/apache/cassandra/blob/cassandra-2.0/src/java/org/apache/cassandra/tools/NodeCmd.java#L955-L956]
in CFSTATS command of nodetool. I've read the documentation from yammer for Histograms and
there is no way to force values to expire after x minutes except by [clearing|http://grepcode.com/file/repo1.maven.org/maven2/com.yammer.metrics/metrics-core/2.1.2/com/yammer/metrics/core/Histogram.java#96]
it . The only thing I can see is that the last snapshot used to provide the median (or whatever
you'd used instead) value is based on 1028 values.
> I think we should also be able to detect that some requests are accessing a lot of live/tombstone
cells per query and that's not possible for now without activating DEBUG for SliceQueryFilter
for example and by tweaking the threshold. Currently as nodetool cfstats returns the median
if a low part of the queries are scanning a lot of live/tombstone cells we miss it !



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

Mime
View raw message