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.

Re: Cassandra Snapshots and directories

[Anthony Grasso]

Hi Daniel,

Yes, you are right it does require some additional work to rsync just the
snapshots.

What about doing something like this to make rsync syntax for the backup
easier?

# in the Cassandra data directory, iterate through the keyspaces
for ks in $(find . -type d -iname backup)
do
  # iterate through each column family in the keyspace
  for cf in $(ls ${ks})
  do
# get the directory without the 'backup' path component in it
out_ks=$(echo ${ks} | cut -d'/' -f2,3)

# make backup directory and perform the rsync
mkdir -p /${out_ks}/${cf}
rsync -azP ${ks}/${cf}/ /${out_ks}/${cf}
  done
done

Regards,
Anthony

On 12 May 2017 at 18:00, Daniel Hölbling-Inzko <
daniel.hoelbling-in...@bitmovin.com> wrote:

> Hi Varun,
> yes you are right - that's the structure that gets created. But if I want
> to backup ALL columnfamilies at once this requires a quite complex rsync as
> Vladimir mentioned.
> I can't just copy over the /data/keyspace directory as that contains all
> the data AND all the snapshots. I really have to go through this
> columnfamily by columnfamily which is annoying.
>
> greetings Daniel
>
> On Thu, 11 May 2017 at 22:48 Varun Gupta  wrote:
>
>>
>> I did not get your question completely, with "snapshot files are mixed
>> with files and backup files".
>>
>> When you call nodetool snapshot, it will create a directory with snapshot
>> name if specified or current timestamp at /data//<
>> columnfamily>/backup/. This directory will have all
>> sstables, metadata files and schema.cql (if using 3.0.9 or higher).
>>
>>
>> On Thu, May 11, 2017 at 2:37 AM, Daniel Hölbling-Inzko <
>> daniel.hoelbling-in...@bitmovin.com> wrote:
>>
>>> Hi,
>>> I am going through this guide to do backup/restore of cassandra data to
>>> a new cluster:
>>> http://docs.datastax.com/en/cassandra/2.1/cassandra/
>>> operations/ops_backup_snapshot_restore_t.html#task_ds_cmf_11r_gk
>>>
>>> When creating a snapshot I get the snapshot files mixed in with the
>>> normal data files and backup files, so it's all over the place and very
>>> hard (especially with lots of tables per keyspace) to transfer ONLY the
>>> snapshot.
>>> (Mostly since there is a snapshot directory per table..)
>>>
>>> Am I missing something or is there some arcane shell command that
>>> filters out only the snapshots?
>>> Because this way it's much easier to just backup the whole data
>>> directory.
>>>
>>> greetings Daniel
>>>
>>
>>