Pulsar reader doesn't return correct last message with startMessageIdInclusive()

[maimom1924]

I want to read last message from topic "A" by using Pulsar Reader as shown in below code:

Reader<byte[]> reader= pulsarClient.newReader()
                    .topic("A")
                    .startMessageIdInclusive()
                    .startMessageId(MessageId.latest)
                    .create();
if(reader.hasMessageAvailable()) {
    Message<byte[]> msg= reader.readNext();
}

Before executing the above code, I have produced many messages on that topic and as the result:

• The msg that I get here is not the last message but the last message - 1 when I add .startMessageIdInclusive()
• Without adding .startMessageIdInclusive(), reader.hasMessageAvailable() will return false.

Pulsar version that I used:

• Version of pulsar jar: 2.5.0
• Version of pulsar for run my pulsar instance: 2.7.0

[zymap]

@maimom1924 Looks like this issue already addressed by this PR #6362. You can try with 2.5.1 or higher version to test it.

[codelipenghui]

@maimom1924 @zymap I will close this issue first, feel free to reopen it if needed.

[maimom1924]

Thank you so much for your help and support. I tried to test with version 2.5.1 but when there is no message on the topic and I call the reader.hasMessageAvailable(), I got true value. Could you please help check on this? Reader<byte[]> reader = pulsarClient.newReader() .topic(config.getStateTopic()) .startMessageId(MessageId.latest) .startMessageIdInclusive() .create(); boolean hasMessage = reader.hasMessageAvailable();

[zymap]

@maimom1924 I think it's the right behavior because you specified the startMessageIdInclusive which means you can read out the last message.

[maimom1924]

so even though there is no message, that should return true, right?

…

On Mon, Feb 1, 2021, 10:09 AM Yong Zhang ***@***.***> wrote: @maimom1924 <https://github.com/maimom1924> I think it's the right behavior because you specified the startMessageIdInclusive which means you can read out the last message. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#9330 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ASTNJLPKDQB4ZMVGVBZLO4LS4X5M5ANCNFSM4WT4NA2A> .

[zymap]

Yes. After reading the last message, then the reader. hasMessageAvailable will return false.

[maimom1924]

@zymap I mean that the topic is completely empty, so the reader. hasMessageAvailable should return false, right? but I got true value.

[zymap]

Sorry for my misunderstanding. Yes, if the topic is empty, it should return false.

I found there has some PRs are fixing this issue: #9316 and #8735

[adrianog]

How do you use this in python? I see no provision at all for startMessageIdInclusive .