incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Alexander Shutyaev <shuty...@gmail.com>
Subject Re: cassandra performance problems
Date Fri, 06 Dec 2013 07:18:14 GMT
Thanks for your answers,

Jonathan, yes it was load avg and iowait was lower than 2% all that time -
the only load was the user one.

Robert, we had -Xmx4012m which was automatically calculated by the default
cassandra-env.sh (1/4 of total memory - 16G) - we didn't change that.


2013/12/5 Robert Coli <rcoli@eventbrite.com>

> On Thu, Dec 5, 2013 at 4:33 AM, Alexander Shutyaev <shutyaev@gmail.com>wrote:
>
>> Cassandra version is 2.0.3. ... We've plugged it into our production
>> environment as a cache in front of postgres.
>>
>
> https://engineering.eventbrite.com/what-version-of-cassandra-should-i-run/
>
>
>> What can be the reason? Can it be high number of tables? Do we need to
>> adjust some settings for this setup? Is it ok to have so many tables?
>> Theoretically we can stuck them all in 3-4 tables.
>>
>
> 500 column families ("tables") is "a lot" but not necessarily "too many."
>
> During that time cluster read latency goes from 2ms to 200ms
>>
>
> In perfectly normal operation, things operating in the JVM may exhibit a
> few hundreds of milliseconds of latency, when the JVM pauses for garbage
> collection. If you absolutely require consistent latency below this time
> for all requests, something running in the JVM may not be for you.
>
> If compaction triggers "runaway GC" then you probably have too much steady
> state heap consumption. You don't mention anything about the hardware
> environment, how much heap is available, etc.. ?
>
> =Rob
>

Mime
View raw message