Detecting Hinted Handoff

Sargun Dhillon sargun at sargun.me
Sun Jul 24 23:48:32 EDT 2016


It might also make a lot of sense to roll your own secondary indices. That
is, have a CRDT set represent the primary key of the rows which meet the 2i
condition. In that, you can query the CRDT set, and ensure some level of
consistency. There are further tricks to be played here if interested.

I'm curious, what is your data model?

On Fri, Jul 22, 2016 at 11:01 AM, Alexander Sicular <siculars at gmail.com>
wrote:

> Take a look at the "pw" and "pr" tunable consistency options for gets and
> puts. The base level of abstraction in Riak is the virtual node - not the
> physical machine. When data is replicated it is replicated to a replica set
> of virtual nodes. Those virtual nodes have primary and secondary (due to
> failures) allocations to physical machines. When using "pr" and "pw"
> options you instruct Riak to only service the request from virtual nodes
> that are residing on their primarily allocated physical machines. In short,
> by abusing pr/pw you can infer the state of your cluster from your
> application.
>
> Obviously, this is not foolproof. There may also be additional 2i specific
> issues to consider. Nevertheless, I always liked this trick.
>
> Also, review this four part series on tunable consistency :
>
>
> http://basho.com/posts/technical/understanding-riaks-configurable-behaviors-part-1/
> http://basho.com/posts/technical/riaks-config-behaviors-part-2/
> http://basho.com/posts/technical/riaks-config-behaviors-part-3/
> http://basho.com/posts/technical/riaks-config-behaviors-part-4/
>
> -Alexander
>
>
> @siculars
> http://siculars.posthaven.com
>
> Sent from my iRotaryPhone
>
> On Jul 22, 2016, at 12:28, Hawk Newton <hawk.newton at gmail.com> wrote:
>
> I've got a use case in which I'd like to use a secondary index but can't
> tolerate partial result sets caused by hinted handoffs.  I'm not currently
> running riak search and, as this is a fringe case, would prefer not add the
> additional overhead and complexity if I can help it.
>
> I'd like to detect a hinted handoff operation and throw a 503, if possible.
>
> Does anyone know of a way I can programatically detect if a hinted handoff
> is underway without having to shell out to riak-admin (yuck!) and parse the
> results? I'm running riak 2.0.5 at the moment.
>
> Thank you in advance.
>
> -- Hawk
>
>
>
> --
> View this message in context:
> http://riak-users.197444.n3.nabble.com/Detecting-Hinted-Handoff-tp4034489.html
> Sent from the Riak Users mailing list archive at Nabble.com
> <http://nabble.com>.
>
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