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From Jon Haddad <...@jonhaddad.com>
Subject Re: Question on large partition key
Date Tue, 31 Dec 2019 19:42:22 GMT
I suggest checking out Aaron Morton's post on the 3.0 storage engine.

https://thelastpickle.com/blog/2016/03/04/introductiont-to-the-apache-cassandra-3-storage-engine.html

On Tue, Dec 31, 2019 at 11:20 AM Subroto Barua <sbarua116@yahoo.com.invalid>
wrote:

> I have a table ---
>
> create Table mytable (
>
> Id text,
>
> cdate timestamp,
>
> Tk text,
>
> Primary key (id, cdate)
>
> ) with clustering order by (cdate desc);
>
> One of the partition key has 2,099,414 rows; using the following formula:
>
> row_size = sum_of_all_columns_ size_within_row + partition_key_size
> row_size = 32bytes (string) + 8 + 32 == 72 bytes
>
> partition_size = row_ size_average * number_of_rows_in_this_partition
> partition_size = 72 * 2099414 = 147,615 KB
>
> Cassandra system log reports: 128,064,307 bytes for this key
>
> Can someone explain the gap? Did I make any wrong assumption in
> calculating the row size/pk size?
>
> C* version is 3.0.15
>
> Thanks,
>
> Subroto
>
>

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