Re: Reg:- Data Modelling based on Update History details

[Anthony Grasso]

Hi Nandan,

Interesting project!

One thing that helps define the schema is knowing what queries will be made
to the database up front. It sounds like you have an idea already of what
those queries will be. I want to confirm that these are the queries that
the database needs to answer.

   - *What are the current details of a book?*
   - *What is the most recent update to a particular book?*
   - *What are the updates that have been made to a particular book?*
   - *What are the details for a particular update?*


Do the above queries sound correct and will the database need to answer any
other queries?

With regards to the data being stored; how frequently do the books get
updated? What type of details are stored for an update, as in, is it meta
information about the book (author, publish date etc) or is it changes to
the book content? Answers to these questions impact the schema structure.

Kind regards,
Anthony

On 15 May 2017 at 16:36, @Nandan@  wrote:

> Hi ,
> I am currently working on Book Management System in which I have a table
> which contains Books details in which PRIMARY KEY is book_id uuid.
> The requirement is to create DB in which we have to keep data of Updated
> values as well as which user update the particular book details and what
> they update.
>
> For example:-
> id:- 1
> Name: - Harry Poter
> Author : - JK Rolling
>
> New Update Done by user_id 2:-
> id :- 1
> Name:- Harry Pottor
> Author:- J.K. Rolls
>
> So I need to update the details of Book which is done by UPSERT. But also
> I have to keep details like which user updated and what updated.
>
> I hope, I am able to describe my scenario in details. Please suggest on
> above scenario.
>
>

Amazon linux upgrade

[Nitan Kainth]

Hi,

We are planning to upgrade Amazon linux to 2017.03. Can someone please point us 
to compatibility matrix for linux with C*?

We are currently at C* 3.0.10.1443 and Linux: NAME="Amazon Linux AMI” 
VERSION=“2016.03"

Thank you
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Re: Moving SSTable to fix JBOD imbalance

[Alain RODRIGUEZ]

>
> Can I just stop the node, move the 56Go SSTable (so I guess the Summary,
> TOC, Digest, Statistics, CompressionInfo, Data, Index and Filter files) and
> restart the node?


Yes this should work, service should stay up as long as all the operations
are performed following this rule: Consistency Level < Replication Factor.
SSTable will be loaded at start time, no matter which disk it is in. But
luckily you don't have to trust me on this one, as it should be easy enough
to test on a dev environment.

within a 3-nodes C* 2.1.4 cluster


I really recommend you to go to C* 2.1.17 as minor upgrades use to be safe
enough while running using the early minor versions of a major Cassandra
version is known to be a source of problems. Many things were fixed or
improved between C* 2.1.4 and C* 2.1.17.

C*heers,
---
Alain Rodriguez - @arodream - al...@thelastpickle.com
France

The Last Pickle - Apache Cassandra Consulting
http://www.thelastpickle.com

2017-05-12 11:52 GMT+01:00 Axel Colin de Verdiere :

> Hello !
>
> I'm experiencing a data imbalance issue with one of my nodes within a
> 3-nodes C* 2.1.4 cluster. All of them are using JBOD (2 physical disks),
> and this particular node seems to have recently made a relatively big
> compaction (I'm using STCS), creating a 56Go SSTable file, which results in
> one of the disks being 94% used and the other only 34%. I've looked around
> for similar issues, and this was supposed to be fixed in 2.1.3 (
> CASSANDRA-7386 ). DSE
> docs
> 
>  suggest
> stopping the node and moving some SSTables around between the disks to
> force a better balance, while trying to make as few moves as possible. Can
> I just stop the node, move the 56Go SSTable (so I guess the Summary, TOC,
> Digest, Statistics, CompressionInfo, Data, Index and Filter files) and
> restart the node?
>
> Thanks a lot for your help,
> Best,
>
> Axel
>

Reg:- Data Modelling based on Update History details

[@Nandan@]

Hi ,
I am currently working on Book Management System in which I have a table
which contains Books details in which PRIMARY KEY is book_id uuid.
The requirement is to create DB in which we have to keep data of Updated
values as well as which user update the particular book details and what
they update.

For example:-
id:- 1
Name: - Harry Poter
Author : - JK Rolling

New Update Done by user_id 2:-
id :- 1
Name:- Harry Pottor
Author:- J.K. Rolls

So I need to update the details of Book which is done by UPSERT. But also I
have to keep details like which user updated and what updated.

I hope, I am able to describe my scenario in details. Please suggest on
above scenario.