[zeromq-dev] pub/sub topic matching on sender side

[Martin Sustrik]

Pieter Hintjens wrote:
> On Fri, Aug 13, 2010 at 10:17 PM, Martin Sustrik <sustrik at 250bpm.com> wrote:
> 
>> Yes. It would actually be a good first step. It would require:
>>
>> 1. Writing the matching engine that is both efficient and can match
>> multiple sets of subscriptions in a single go.
> 
>> Tackling pt.1 would be a good exercise in algorithms and data structures :)
> 
> Just curious, what is not efficient about the current algorithm?

It is efficient. But being inside SUB socket it sends messages to a 
single destination only (the user). Thus the output from the filter is 
just a bit (pass/drop).

If it's on the PUB side there can be several destinations to send the 
messages to, so the outcome of filtering would be rather a bit-vector.

Martin