Reading from big partitions

[onmstester onmstester]

Hi, 

Due to some unpredictable behavior in input data i end up with some hundred 
partitions having more than 300MB size. Reading any sequence of data

from these partitions took about 5 seconds while reading from other partitions 
(with less than 50MB sizes) took less than 10ms.

Since i can't change the data model in sake of a few problematic partitions, Is 
there any tuning at Cassandra side that could boost up read performance from 
the big partitions?

Thanks in advance



Sent using Zoho Mail

Re: Reading from big partitions

[Jonathan Haddad]

What disks are you using? How many sstables are you hitting? Did you try
tracing the request?

On Sat, May 19, 2018 at 8:43 PM onmstester onmstester 
wrote:

> Hi,
> Due to some unpredictable behavior in input data i end up with some
> hundred partitions having more than 300MB size. Reading any sequence of data
> from these partitions took about 5 seconds while reading from other
> partitions (with less than 50MB sizes) took less than 10ms.
> Since i can't change the data model in sake of a few problematic
> partitions, Is there any tuning at Cassandra side that could boost up read
> performance from the big partitions?
> Thanks in advance
>
> Sent using Zoho Mail 
>
>
> --
Jon Haddad
http://www.rustyrazorblade.com
twitter: rustyrazorblade

Re: Reading from big partitions

[Jeff Jirsa]

Column index size in the yaml (increase it to trade GC pressure for disk IO)

If you’re on anything other than 3.11.x, upgrade to 3.11.newest



-- 
Jeff Jirsa


> On May 19, 2018, at 8:42 PM, onmstester onmstester  
> wrote:
> 
> Hi, 
> Due to some unpredictable behavior in input data i end up with some hundred 
> partitions having more than 300MB size. Reading any sequence of data
> from these partitions took about 5 seconds while reading from other 
> partitions (with less than 50MB sizes) took less than 10ms.
> Since i can't change the data model in sake of a few problematic partitions, 
> Is there any tuning at Cassandra side that could boost up read performance 
> from the big partitions?
> Thanks in advance
> 
> Sent using Zoho Mail
> 
> 
> 

Question About Reaper

[Surbhi Gupta]

Hi,

We have a cluster with 144 nodes( 3 datacenter) with 256 Vnodes .
When we tried to start repairs from opscenter then it showed 1.9Million
ranges to repair .
And even after doing compaction and strekamthroughput to 0 , opscenter is
not able to help us much to finish repair in 9 days timeframe .

What is your thought on Reaper ?
Do you think , Reaper might be able to help us in this scenario ?

Thanks
Surbhi