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From onmstester onmstester <>
Subject Re: write latency on single partition table
Date Sat, 07 Apr 2018 05:05:47 GMT
The size is less than 50MB

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---- On Sat, 07 Apr 2018 09:09:41 +0430 Laxmikant Upadhyay &lt;;
wrote ----

It seems your partition size is more..what is the size of value field ? Try to keep your partition
size within 100 mb.

On Sat, Apr 7, 2018, 9:45 AM onmstester onmstester &lt;; wrote:

I've defained a table like this

create table test (

hours int,

key1 int,

value1 varchar,

primary key (hours,key1)


For one hour every input would be written in single partition, because i need to group by
some 500K records in the partition for a report with expected response time in less than 1
seconds so using key1 in partition key would made 500K partitions which would be slow on reads.

Although using  this mechanism gains &lt; 1 seconds response time on reads but the write
delay increased surprisingly, for this table write latency reported by cfstats is more than
100ms but for other tables which accessing thousands of partitions while writing in 1 hour
, the write delay is 0.02ms. But i was expecting that writes to test table be faster than
other tables because always only one node and one partition would be accessed, so no memtable
switch happens and all writes would be local to a single node?!

Should i add another key to my partition key to distribute data on all of nodes?

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