This seems a bit overkill. We run far more than 100mps (closer to 600) in rabbit with very good latency on a 3 node cluster. It has been very reliable as well. 

Thunder

----- Reply message -----
From: "Jagan Ranganathan" <jagan@zohocorp.com>
To: <user@cassandra.apache.org>
Subject: Queuing System
Date: Sat, Feb 22, 2014 9:06 AM

Thanks Tupshin for your assistance. As I mentioned in the other mail, 
Yes I am planning to use RabbitMQ for my messaging system. But I wonder which will give better performance if writing directly into Rabbit with Ack support Vs a temporary Queue in Cassandra first and then dequeue and publish in Rabbit.
I use Rabbit for Messaging because of the Routing and Push model communication etc. So I am thinking of using Cassandra as a temporary Queue which will give fast write performance with no data loss Vs waiting for Rabbit Ack @ application level or handling Rabbit re-connection Vs Cassandra hinted handoff writes.

So Cassandra might aggregate all my msg queue temporarily before I publish them to Rabbit. Is this fine? If so, please share your insight on which model & access pattern will be a better fit for this usage. Throughput requirements may be around say 100 ops/sec.

Regards,
Jagan

---- On Sat, 22 Feb 2014 21:10:36 +0530 Tupshin Harper<tupshin@tupshin.com> wrote ----

While, historically, it has been true that queuing in Cassandra has been an anti-pattern, it is also true that Leveled Compaction addresses the worst aspect of frequent deletes in Cassandra, and that overall, queuing in Cassandra is nowhere near the anti-pattern that it used to be. This is something that I've been meaning to write about more extensively.

 If your requirements are more around availability (particularly multi-dc) and relability with moderate (not extreme) performance, it is quite possible to build a pretty decent system on top of Cassandra. You don't mention your throughput requirements, nor additional semantics that might be necessary (e.g. deliver at-least-once vs deliver exactly once), but Cassandra 2.0's lightweight transactions provide a CAS primitive that can be used to ensure deliver-once if that is a requirement.

I'd be happy to continue discussing appropriate data-models and access patterns if you decide to go down this path.

-Tupshin


On Sat, Feb 22, 2014 at 10:03 AM, Jagan Ranganathan <jagan@zohocorp.com> wrote:
Hi,

I need to decouple some of the work being processed from the user thread to provide better user experience. For that I need a queuing system with the following needs,
  • High Availability
  • No Data Loss
  • Better Performance.
Following are some libraries that were considered along with the limitation I see,
  • Redis - Data Loss
  • ZooKeeper - Not advised for Queue system.
  • TokyoCabinet/SQLite/LevelDB - of this Level DB seem to be performing better. With replication requirement, I probably have to look at Apache ActiveMQ+LevelDB.
After checking on the third option above, I kind of wonder if Cassandra with Leveled Compaction offer a similar system. Do you see any issues in such a usage or is there other better solutions available.

Will be great to get insights on this.

Regards,
Jagan