Checkpoint records



  • 11.7 introduces the "-numCheckpointStats" param, defaulting to 32. So _checkpoint will have more records than in the past.

    It appears the PT "Checkpoints" browse is always sized for 8 rows. Just wondering if you've thought about changing that.


  • administrators

    Have a thought about it?

    Yep.

    Done anything about it?

    Nope.

    How important would you say that it is?



  • Well it certainly isn't life or death. But I agree with Rich: "a history of 8 is not a history". There have been many times where I've looked at a DB in promon and seen the last 8 checkpoints bunched up over the last hour or two, but the customer is complaining that "the batch run was slow last night". That checkpoint data is long gone.

    So a new default of 32, with the ability to go higher, is certainly a welcome change. And if PT doesn't show all the history, I guess that's okay. The table is easy enough to query if I need to.


  • administrators

    The ChUI ProTop is mostly focused on what is going on right now. Historical data is presented on the web portal.

    Of course the portal doesn't currently have a lot of checkpoint oriented data. I'd be interested in how you might want to visualize historical checkpoint data.



  • I think the key metrics are length (say, in minutes), buffers flushed, duration, and sync time.

    So that could be shown as four separate graphs. Or, given the three-across layout of the portal, you could have a "Checkpoints" row with a graph for length, one for buffers flushed, and then a dual-axis graph for duration and sync time.

    I think the existing grafana graphs are appropriate for this data, as they are for the other metrics.


  • administrators

    That makes sense.

    Thanks!



  • I would like to see historical Checkpoint information on the portal.
    It would help to verify changes to biclustersize


 

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