Cassandra use cases: as a datagrid ? as a distributed cache ?

[Dominique De Vito]

Hi,

Cassandra comes closer and closer to a data grid like Oracle Coherence:
Cassandra includes distributed "hash maps", partitioning, high
availability, map/reduce processing, (some) request capability, etc.

So, I am wondering about the 2 following (and possible ?) Cassandra's
use cases :

(1) has anyone already used Cassandra as an in-memory data grid ?
If no, does anyone know how far such a database is from, let's say,
Oracle Coherence ?
Does Cassandra provide, for example, a (synchronized) cache on the
client side ?

(2) has anyone already used Cassandra as a distributed cache ?
Are there some testimonials somewhere about this use case ?

Thanks for your help.

Regards,
Dominique

[Jonathan Ellis]

On Mon, Apr 26, 2010 at 9:04 AM, Dominique De Vito

Post by Dominique De Vito
(1) has anyone already used Cassandra as an in-memory data grid ?
If no, does anyone know how far such a database is from, let's say, Oracle
Coherence ?
Does Cassandra provide, for example, a (synchronized) cache on the client
side ?

If you mean an in-process cache on the client side, no.

Post by Dominique De Vito
(2) has anyone already used Cassandra as a distributed cache ?
Are there some testimonials somewhere about this use case ?

That's basically what reddit is using it for.
http://blog.reddit.com/2010/03/she-who-entangles-men.html

[Joseph Stein]

great talk tonight in NYC I attended in regards to using Cassandra as
a Lucene Index store (really great idea nicely implemented)
http://blog.sematext.com/2010/02/09/lucandra-a-cassandra-based-lucene-backend/

so Lucinda uses Cassandra as a distributed cache of indexes =8^)

Post by Jonathan Ellis
On Mon, Apr 26, 2010 at 9:04 AM, Dominique De Vito

Post by Dominique De Vito
(1) has anyone already used Cassandra as an in-memory data grid ?
If no, does anyone know how far such a database is from, let's say, Oracle
Coherence ?
Does Cassandra provide, for example, a (synchronized) cache on the client
side ?

If you mean an in-process cache on the client side, no.

Post by Dominique De Vito
(2) has anyone already used Cassandra as a distributed cache ?
Are there some testimonials somewhere about this use case ?

That's basically what reddit is using it for.
http://blog.reddit.com/2010/03/she-who-entangles-men.html
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

[Joseph Stein]

(sp) Lucandra http://github.com/tjake/Lucandra

Post by Joseph Stein
great talk tonight in NYC I attended in regards to using Cassandra as
a Lucene Index store (really great idea nicely implemented)
http://blog.sematext.com/2010/02/09/lucandra-a-cassandra-based-lucene-backend/
so Lucinda uses Cassandra as a distributed cache of indexes =8^)

Post by Jonathan Ellis
On Mon, Apr 26, 2010 at 9:04 AM, Dominique De Vito

Post by Dominique De Vito
(1) has anyone already used Cassandra as an in-memory data grid ?
If no, does anyone know how far such a database is from, let's say, Oracle
Coherence ?
Does Cassandra provide, for example, a (synchronized) cache on the client
side ?

If you mean an in-process cache on the client side, no.

Post by Dominique De Vito
(2) has anyone already used Cassandra as a distributed cache ?
Are there some testimonials somewhere about this use case ?

That's basically what reddit is using it for.
http://blog.reddit.com/2010/03/she-who-entangles-men.html
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

--
/*
Joe Stein
http://www.linkedin.com/in/charmalloc
*/

[Lisen Mu]

http://www.reddit.com/r/programming/comments/bcqhi/reddits_now_running_on_cassandra/

It seems to me that they are still using Cassandra in persistant storage
layer as a replacement of memcachedb, not in cache layer.

I'm new here with Cassandra actually, but now I'm also curious about the
possibility of using cassandra as cache.
the main concern is repair-on-read strategy, the secondary is commitlog.

If I'm correct about this, every read request to cassandra will trigger
several (N-1) message between cassandra nodes.
In our current traditional memcached + mysql set up, our intranet is kind of
busy already. I think It would be a burden if message is flooding between
memcached servers.

In fact, In my opinion, what happend to our db is happening again in cache
layer:

First, we have nonsql Cassandra, saver of the day.
But we are not going to let Cassandra carry the weight of page view
directly, so we still need cache.
Eventually we have to shard the cache to scale, and replicate to handle hot
spot.
In this stage, it would be a HUGE pity if we cannot reuse Cassandra's
exclusively outstanding ability of handling distribution problem.

So why not provide a kind of Cassandra Daemon, so we can write adapter for
memcached etc. to construct a pure-in-memory distributed cache layer?

Post by Jonathan Ellis
On Mon, Apr 26, 2010 at 9:04 AM, Dominique De Vito

Post by Dominique De Vito
(1) has anyone already used Cassandra as an in-memory data grid ?
If no, does anyone know how far such a database is from, let's say,

Oracle

Post by Dominique De Vito
Coherence ?
Does Cassandra provide, for example, a (synchronized) cache on the client
side ?

If you mean an in-process cache on the client side, no.

Post by Dominique De Vito
(2) has anyone already used Cassandra as a distributed cache ?
Are there some testimonials somewhere about this use case ?

That's basically what reddit is using it for.
http://blog.reddit.com/2010/03/she-who-entangles-men.html
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

[Lisen Mu]

Facebook did a lot of work to keep their huge memcache
cluster consistent and fault-tolerant.
I think a cache infrastructure like Cassandra would make that a lot easier.

Post by Lisen Mu
http://www.reddit.com/r/programming/comments/bcqhi/reddits_now_running_on_cassandra/
It seems to me that they are still using Cassandra in persistant storage
layer as a replacement of memcachedb, not in cache layer.
I'm new here with Cassandra actually, but now I'm also curious about the
possibility of using cassandra as cache.
the main concern is repair-on-read strategy, the secondary is commitlog.
If I'm correct about this, every read request to cassandra will trigger
several (N-1) message between cassandra nodes.
In our current traditional memcached + mysql set up, our intranet is kind
of busy already. I think It would be a burden if message is flooding between
memcached servers.
In fact, In my opinion, what happend to our db is happening again in cache
First, we have nonsql Cassandra, saver of the day.
But we are not going to let Cassandra carry the weight of page view
directly, so we still need cache.
Eventually we have to shard the cache to scale, and replicate to handle hot
spot.
In this stage, it would be a HUGE pity if we cannot reuse Cassandra's
exclusively outstanding ability of handling distribution problem.
So why not provide a kind of Cassandra Daemon, so we can write adapter for
memcached etc. to construct a pure-in-memory distributed cache layer?

Post by Jonathan Ellis
On Mon, Apr 26, 2010 at 9:04 AM, Dominique De Vito

Post by Dominique De Vito
(1) has anyone already used Cassandra as an in-memory data grid ?
If no, does anyone know how far such a database is from, let's say,

Oracle

Post by Dominique De Vito
Coherence ?
Does Cassandra provide, for example, a (synchronized) cache on the

client

Post by Dominique De Vito
side ?

If you mean an in-process cache on the client side, no.

Post by Dominique De Vito
(2) has anyone already used Cassandra as a distributed cache ?
Are there some testimonials somewhere about this use case ?

That's basically what reddit is using it for.
http://blog.reddit.com/2010/03/she-who-entangles-men.html
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com