I didn't know about this cfhistograms thing, very nice!
From: user@cassandra.apache.org
Subject: Re: Unexplained query slowness
Have a look at your column family histograms (nodetool cfhistograms iirc), if
you notice things like a very long tail, a double hump or outliers it would
ind
Have a look at your column family histograms (nodetool cfhistograms iirc),
if you notice things like a very long tail, a double hump or outliers it
would indicate something wrong with your data model or you have a hot
partition key/s.
Also looking at your 99 and 95 percentile latencies will just h
You can use query tracing to check what is happening. Also you fire
jconsole/JavaVisualVM and push out some metrics like the 99th read Beans
for that column family.
A simpler check is using cfstats and look for weird numbers (high number
sstables, if you are deleting check how much tombstones per s
Our Cassandra database just rolled to live last night. I’m looking at our query
performance, and overall it is very good, but perhaps 1 in 10,000 queries takes
several hundred milliseconds (up to a full second). I’ve grepped for GC in the
system.log on all nodes, and there aren’t any recent GC e
