On Mon, Feb 27, 2017 at 10:30 AM, Romain Hardouin <romainh...@yahoo.fr>
wrote:
> Hi,
>
> Regarding shared pool workers see CASSANDRA-11966. You may have to
> backport it depending on your Cassandra version.
>
*we are currently using 3.0.9. should we use 3.8 or 3.10?*
>
> Did you try to lower compaction throughput to see if it helps? Be sure to
> keep an eye on pending compactions, SSTables count and SSTable per read of
> course.
>
*I haven't done any tuning yet. Can I change this on a running instance?
If so, how? or does it require a downtime?*
>
> "alloc" is the memory allocation rate. You can see that compactions are GC
> intensive.
>
> You won't be able to achieve impressive writes/s with LWT. But maybe there
> is room for improvement. Try GC tuning, different pool sizes for NTR,
> concurrent reads and writes, compaction executors, etc. Also check if you
> can improve network latency (e.g. VF or ENA on AWS).
>
* GC seems to be fine because when I checked GC is about 0.25%. Total GC
time is about 6minutes since the node is up and running for about 50 hours*.
>
> What LWT rate would you want to achieve? *5000 is the target.*
>
> Best,
>
> Romain
>
>
>
> Le Lundi 27 février 2017 12h48, Kant Kodali <k...@peernova.com> a écrit :
>
>
> Also Attached is a flamed graph generated from a thread dump.
>
> On Mon, Feb 27, 2017 at 2:32 AM, Kant Kodali <k...@peernova.com> wrote:
>
> Hi,
>
> Attached are the stats of my Cassandra node running on a 4-core CPU. I am
> using sjk-plus tool for the first time so what are the things I should
> watched out for in my attached screenshot? I can see the CPU is almost
> maxed out but should I say that is because of compaction or
> shared-worker-pool threads (which btw, I dont know what they are doing
> perhaps I need to take threadump)? Also what is alloc for each thread?
>
> I have a insert heavy workload (almost like an ingest running against
> cassandra cluster) and in my case all writes are LWT.
>
> The current throughput is 1500 writes/sec where each write is about 1KB.
> How can I tune something for a higher throughput? Any pointers or
> suggestions would help.
>
> Thanks much,
> kant
>
>
>
>
>
