Hello, Thank you for the reply. I agree that PowerDNS launches several backend threads and they handle requests concurrently. When using Remote, especially with ZeroMQ, it sends a single request regarding a domain and will wait for an answer for that specific domain, since the REQ/REP pattern is not able to send() new queries before it receives data. In this scenario it is not possible to write a recipient back-end that connects through remote and handles several requests synchronously.
On Sun, Sep 11, 2016 at 10:44 PM, Aki Tuomi <cmo...@youzen.ext.b2.fi> wrote: > On Sun, Sep 11, 2016 at 06:23:05PM +0300, Viktor Velchev wrote: > > Hello, > > > > I am running PowerDNS 4.0.1, which is complied from source with ZeroMQ > > support in a Debian 8 environment. I am experimenting with Remote and I > am > > willing to write my own DNS storage (back-end), which connects to > PowerDNS > > through Remote. Changelogs for the newer PowerDNS versions do not give > any > > hints regarding the bellow described problem, so I think it is safe to > > assume that the case will be the same with all available 4.0.x releases. > > > > I am launching a single Remote instance and several threads: > > launch=remote > > distributor-threads=4 > > receiver-threads=4 > > > > Receiver and distributor thread count is just an example, the point is > that > > I am not running in single threaded mode. > > > > The main problem is that Remote itself does not give me any options to > > create a multi-threaded back-end. I have checked the source and although > > ZeroMQ is configured to start two I/O threads, but the implemented > REQ/REP > > pattern limits the communication to: > > > > 1. PowerDNS sends a request about a domain. > > 2. PowerDNS waits (blocks) until it receives data about the domain. > > > > Once my back-end receives a request I am limited to either returning > false > > or replying. > > I am pretty sure that the case is the same with the Unix socket > connector. > > I have NOT checked if the case is the same with the HTTP connector. > > > > My questions are: > > 1. Is there a possibility to modify the communication pattern, so that > > PowerDNS either submits multiple requests through Remote OR maybe add a > > command which asks for a new query while the previous one is being > executed? > > 2. In case I have myself misunderstood the way PowerDNS operates, is > there > > a Remote connector which is suited for use in cases where the recipient > > wants to handle multiple requests at a time? > > > > Best Regards, > > Victor > > Usually powerdns launches several backend threads, each working in blocking > mode. Thus you will have concurrent requests running despite remotebackend > only doing one request at a time. > > Aki >
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