[CASSANDRA-7731] Get max values for live/tombstone cells per slice

• Type: Improvement
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 2.2.0
• Assignee: Robert Stupp
• Reporter: Cyril Scetbon

Authors

Robert Stupp

Reviewers

Jeremiah Jordan

• Created: 09/Aug/14 22:14
• Updated: 16/Apr/19 09:31
• Resolved: 09/Aug/15 18:35

Description

I think you should not say that slice statistics are valid for the last five minutes 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 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 !