Hi Nico, we wanted to upgrade to 3.11.8 (from .6), but now I'm very concerned as our load is mostly read-only and very latency sensitive. Did you figure out the reason for such behaviour with the new version ?
Regards, Maxim. On Tue, Sep 15, 2020 at 5:24 AM Sagar Jambhulkar <sagar.jambhul...@gmail.com> wrote: > That is odd. I thought maybe lower version had a bigger custom cache or > some other setting missed in the upgrade. > > On Mon, 14 Sep 2020, 23:00 Nicolai Lune Vest, <nicolai.v...@lancom.de> > wrote: > >> While cache configuration stays the same, cache hit rate for both, the >> chunk cache and the key cache are worse (but still ok) after the update. >> You can see the change in the attached screenshot (update was performed at >> September the 7th ~4pm). >> >> @Sagar Any specific reason you are suspecting the cache? >> >> >> >> -----"Sagar Jambhulkar" <sagar.jambhul...@gmail.com> schrieb: ----- >> An: user@cassandra.apache.org >> Von: "Sagar Jambhulkar" <sagar.jambhul...@gmail.com> >> Datum: 14.09.2020 16:25 >> Betreff: Re: Increased read latency with Cassandra >= 3.11.7 >> >> >> Maybe compare the cache size see if anything different in two versions? >> >> >> On Mon, 14 Sep 2020, 19:21 Nicolai Lune Vest, <nicolai.v...@lancom.de> >> wrote: >> >> >> Dear Cassandra community, >> >> after upgrading my Cassandra nodes from version 3.11.6 to either 3.11.7 >> or 3.11.8 I experience a significant increase in read latency. >> With 3.11.6 average read latency is ~0.35 ms. With 3.11.7 average read >> latency increases to ~2.9 ms, almost 10 times worse! This behavior applies >> to all my environments, testing and productive. >> >> I do also observe that the "bloom-filter false positive rate" and >> "SSTable reads" increases significantly with version >= 3.11.7 >> >> I'm wondering if someone experienced the same problem when updating >> Cassandra from 3.11.6 to either 3.11.7 or 3.11.8 and can help me out. >> >> I already tried nodetool scrub, sstablescrub, manual compaction, and >> repair on selected tables without impact. When downgrading back to 3.11.6 >> read latency recovers immediately. >> >> My update routine is very simple. I'm just stopping the service, install >> the new version (using apt), and start the service again. One node after >> the other. As coming from 3.11.6 updating to 3.11.7 (or 3.11.8) is just a >> patch update and I expect this routine should do well, but maybe I'm >> missing some important steps here. >> >> I can provide more information about my system or configuration if >> required. >> >> Appreciate your support! >> >> Kind regards >> Nico >> >> >> >> >> >> >> >> LANCOM Systems GmbH >> Adenauerstr. 20 / B2 >> 52146 Würselen >> Deutschland >> >> Tel: +49 2405 49936-0 >> Fax: +49 2405 49936-99 >> >> Web: https://www.lancom-systems.de >> >> >> >> Geschäftsführer: Ralf Koenzen, Stefan Herrlich >> Sitz der Gesellschaft: Aachen, Amtsgericht Aachen, HRB 16976 >> >> >> >> >> >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org >> For additional commands, e-mail: user-h...@cassandra.apache.org > >
