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From Peter Lin <wool...@gmail.com>
Subject Re: Rationale for using Hazelcast in front of Cassandra?
Date Fri, 07 Oct 2016 15:28:02 GMT
Cassandra is a database, not an in-memory cache. Please don't abuse
Cassandra like that when there's plenty of existing distributed cache
products designed for that purpose.

That's like asking "why can't I drag race with a school bus?"

You could and it might be fun, but that's not what it was designed for.

On Fri, Oct 7, 2016 at 11:22 AM, KARR, DAVID <dk068x@att.com> wrote:

> No, I haven’t “thought why people don’t use Cassandra as a cache”, that’s
> why I’m asking this here.  I’m asking the community for their POV when it
> might make sense to front Cassandra with Hazelcast.  This is even mentioned
> as a use case in the Hazelcast documentation (“As a front layer for a
> Cassandra back-end”), and I’m aware of at least one large private
> enterprise that does this.
>
>
>
> *From:* Dorian Hoxha [mailto:dorian.hoxha@gmail.com]
> *Sent:* Friday, October 07, 2016 3:48 AM
> *To:* user@cassandra.apache.org
> *Subject:* Re: Rationale for using Hazelcast in front of Cassandra?
>
>
>
> Primary-key select is pretty fast in rdbms too and they also have caches.
> By "close to" you mean in latency ?
>
> Have you thought why people don't use cassandra as a cache ? While it
> doesn't have LRU, it has TTL,replicatio,sharding.
>
>
>
> On Fri, Oct 7, 2016 at 12:00 AM, KARR, DAVID <dk068x@att.com> wrote:
>
> Clearly, with “traditional” RDBMSs, you tend to put a cache “close to” the
> client.  However, I was under the impression that Cassandra nodes could be
> positioned “close to” their clients, and Cassandra has its own cache (I
> believe), so how effective would it be to put a cache in front of a cache?
>
>
>
> *From:* Dorian Hoxha [mailto:dorian.hoxha@gmail.com]
> *Sent:* Thursday, October 06, 2016 2:52 PM
> *To:* user@cassandra.apache.org
> *Subject:* Re: Rationale for using Hazelcast in front of Cassandra?
>
>
>
> Maybe when you can have very hot keys that can give trouble to your
> 3(replication) cassandra nodes ?
>
> Example: why does facebook use memcache ? They certainly have things
> distributed on thousands of servers.
>
>
>
> On Thu, Oct 6, 2016 at 11:40 PM, KARR, DAVID <dk068x@att.com> wrote:
>
> I've seen use cases that briefly describe using Hazelcast as a "front-end"
> for Cassandra, perhaps as a cache.  This seems counterintuitive to me.  Can
> someone describe to me when this kind of architecture might make sense?
>
>
>
>
>

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