Re: Feature: Mnesia hooks

Sounds interesting, I have a branch which reduces the number of locks
during table copying at startup,
so that will improve the startup time for large systems.

But this sounds interesting, send the PR and I will take a better look at
it.

On Fri, Jan 28, 2022 at 5:59 PM k32 <[email protected]> wrote:

> Hello,
>
> We've been experimenting with the ways to make large Mnesia clusters
> more viable. Our basic idea is to move away from full-mesh topology to a
> "mesh+star" topology: a small part of the cluster behaves like a regular
> mnesia cluster (we call it core cluster) connected in a full mesh, but
> the rest of the nodes are read-only; they passively and asynchronously
> replicate transactions from the core cluster over custom protocol, and
> delegate write operations to the core nodes via RPC, hence "star".
>
> So far this approach looks quite promising, we've been able to achieve
> decent throughput in 20+ node clusters, so this may be a possible
> solution to the mnesia scalability challenge. But we had to patch mnesia
> a bit: https://github.com/emqx/otp/pull/16/files (the initial idea to
> rely on the events alone proved to introduce too much overhead).
>
> Ideally, we would like to contribute this patch upstream, so we're
> seeking the opinion from the OTP team. Hook API may be of use for other
> things too. Not sure if this is the right channel, though.
>
> --
> BR
>