Slack digest for #dev - 2019-08-28

[Apache Pulsar Slack <ap...@gmail.com>]

2019-08-27 13:57:29 UTC - Jianfeng Qiao: While using cpp client, I create a consumer and subscription on a topic, the consumer cannot redeliver the unacked message if I keep changing the time of server running the consumer back and forth.
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2019-08-27 13:59:21 UTC - Jianfeng Qiao: I investigate the code and find out the following code:
void UnAckedMessageTrackerEnabled::timeoutHandler() {
    timeoutHandlerHelper();
    ExecutorServicePtr executorService = client_->getIOExecutorProvider()->get();
    timer_ = executorService->createDeadlineTimer();
    timer_->expires_from_now(boost::posix_time::milliseconds(timeoutMs_));
    timer_->async_wait([&](const boost::system::error_code& ec) {
        if (ec) {
            LOG_DEBUG("Ignoring timer cancelled event, code[" << ec << "]");
        } else {
            timeoutHandler();
        }
    });
}
If I change the time forward before expires_from_now() and afterward after executing expires_from_now(), there will be problem for consumer to redeliver the message
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2019-08-27 14:33:31 UTC - Jianfeng Qiao: I read the doc about deadline timer(<https://www.boost.org/doc/libs/1_66_0/doc/html/boost_asio/reference/deadline_timer.html>), it seems expires_from_now() is using relative time, so I don't quite understand why it is affected by the time change. Anyone have idea about this?
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2019-08-27 15:46:52 UTC - Matteo Merli: even if the specified time is “relative” from the timer API perspective, that doesn’t mean that the internal timer is independent from the system clock
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2019-08-27 15:47:29 UTC - Matteo Merli: typically there are multiple clock types on linux (and other systems have different ways too).
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2019-08-28 00:59:32 UTC - Jianfeng Qiao: @Matteo Merli Is there a way to solve it?
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2019-08-28 01:18:32 UTC - Matteo Merli: We’d need to use std::steady_timer when constructing the Boost Asio deadline_timer. Something like described in <https://stackoverflow.com/questions/16721243/boostasiodeadline-timer-with-stdchrono-time-values>
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2019-08-28 01:26:33 UTC - Jianfeng Qiao: Ok, I'll have a try on this, thanks.:slightly_smiling_face:
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2019-08-28 06:22:23 UTC - Vladimir Shchur: Anyone? I'm writing a dotnet client and don't understand why pending messages are not discarded exceptionally in case of successful close call.
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2019-08-28 08:33:25 UTC - Eugene: @Eugene has joined the channel
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