Would each device/machine have its own keyspace?
Basically, your client needs to take care of a successful creation of the
schema and any other verifications and it is going to be time consuming.
From: Emalayan Vairavanathan
Sent: Thursday, May 23, 2013 3:07 PM
To: user@cassandra.apache.org
Subject: Re: Creating namespace and column family from multiple nodes
concurrently
Hi Arthur and Farraz,
Thank you for getting back to me.
I am trying to avoid sync among concurrent instances and this is why I am
preferring Option - 2. Further in my application, I have reasonable window
between the application initialization phase and the application runtime. So
as long as Cassandra can safely handle concurrent creation I should be fine.
Do you have any idea how Cassandra is going to handle concurrent namespace and
column family creation (Here all the instances are going to create the same
namespace and column families concurrently)?
- Does Cassandra take much time to agree on a final schema (In case if
Cassandra is using some sort of exponential back off algorithms to handle
schema conflicts) ?
- Or is it going to result schema conflicts which needs manual
intervention ?
- Or will this result in race conditions ?
- Or some other issues e.g: memory/ cpu /network bottlenecks ?
Thank you
Emalayan
--------------------------------------------------------------------------------
From: Arthur Zubarev <arthur.zuba...@aol.com>
To: user@cassandra.apache.org; svemala...@yahoo.com
Sent: Wednesday, 22 May 2013 8:07 PM
Subject: Re: Creating namespace and column family from multiple nodes
concurrently
I am assuming here you want to sync all the 100s of nodes once the application
is airborne. I suspect this would flood the network and even potentially affect
the machine itself memory-wise. How are you going to maintain the nodes
(compaction+repair)?
Regards,
Arthur
-----Original Message-----
From: Emalayan Vairavanathan <svemala...@yahoo.com>
To: user <user@cassandra.apache.org>
Sent: Wed, May 22, 2013 8:31 pm
Subject: Creating namespace and column family from multiple nodes concurrently
Hi all,
I am implementing a distributed application which runs on 100s of machines
concurrently. This application is going to use Cassandra as underlaying storage.
The application creates the schema (name space and column families) during
initialization phase. It seems I have two options to create the schema.
Option - 1 : Using a single node for schema creation.
Option - 2: Having all the nodes (> 100) to run the same schema
creation logic (First, nodes will check whether the schema is already available
and then try to create the schema if it is not available already).
To keep the initialization phase simple, I prefer to go for Option - 2. However
I am not sure how Cassandra is going to behave if multiple nodes try to create
the same schema (namespace and column families) concurrently. It would be nice
if someone can tell me about the implications of Option - 2 with Cassandra
version 1.2.2.
Please let me know if you have question.
Thank you
VE
