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Expose msg_backlog_non_delayed metric #6281
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@sijie From the discussion at slack, you have mentioned that
msg_backlog - msg_delayedcan not be reliably used for measuring non-delayed messages. Does this mean we need an accurate way of measuring or just a reminder, we still expose an indicatormsg_backlog_non_delayed=msg_backlog - msg_delayed?I was thinking of finding a more accurate way to measure this.
Thanks @codelipenghui! Specifically, we want the number of messages that are ready to be consumed right now. In other words, we want the number of messages that either were not published with a
deliverAttime, or have adeliverAttime that is on or before the current time.For alerting purposes it should ideally be accurate within a minute or so. The problem we've seen is the number
msg_backlog - msg_delayedcan often be incorrect for a day or more so it is not sufficient for this purpose.Ok, I will take a look.
I created an issue #6045 before.
msg_backlogis an estimated value. It is estimated by minus two cached numbers(numProduced - numConsumed).- linked a pull request that will close this issueEnable get precise backlog and backlog without delayed messages. #6310
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Is your feature request related to a problem? Please describe.
Currently, metric
msg_backlogcontains delayed messages and un-delayed messages. However, users need the number of non-delayed messages in the backlog, which can use by too many un-delayed backlogs alerts. So it's better to addmsg_backlog_non_delayedmetric.Discussion at slack channel: https://apache-pulsar.slack.com/archives/C5Z4T36F7/p1581283048289800