[erlang-questions] Support for newcomers and the popularity of Erlang

Wojciech Knapik <>
Wed Mar 21 02:56:45 CET 2012


On Mon, Mar 19, 2012 at 06:07:16PM +0100, Ulf Wiger wrote:

> - Mnesia uses a simple broadcast algorithm for locking, and 2-phase
> commit protocols, so running transactions across a large number of
> replicas will become increasingly expensive. Ironically, I've often
> heard people become frustrated with mnesia's performance when running
> fully replicated, and instead switch to PostgreSQL, which until very
> recently, couldn't replicate at all. This suggest that replication
> wasn't a requirement in the first place (for them, I don't know enough
> about your requirements to know if it applies in this case).
> 
*SNIP*
>
> I assume the SQL database is not running in fully replicated mode? If
> so, perhaps you have a layered architecture after all?

In our case the mnesia database will only hold data relevant to the
system's operation at any given moment. The loss of this data would
likely be a severe problem.

The SQL database will provide information that's not crucial for the
system to operate, but if it goes down, some of the system's
functionality will be limited. We're still planning to keep it
replicated though.

br,
WK



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