CODEWITHSUNDEEP
graphite
Dean Hiller
Dean Hiller

Reputation: 20182

how to do a sum in graphite but exclude cases where not all data is present

We have 4 data series and once in a while one of the 4 has a null as we missed reading the data point. This makes the graph look like we have awful spikes in loss of volume coming in which is not true as we were just missing the data point.

I am doing a basic sumSeries(server*.InboundCount) right now for server 1, 2, 3, 4 where the * is.

Is there a way where graphite can NOT sum the locations on the line and just have sum for those points in time be also null so it connects the line from the point where there is data to the next point where there is data.

NOTE: We also display the graphs server*.InboundCount individually to watch for spikes on individual servers.

or perhaps there is function such that it looks at all the series and if any of the values is null, it returns null for every series that it takes X series and returns X series points to the sum function as null+null+null+null hopefully doesn't result in a spike and shows null.

thanks, Dean

Upvotes: 3

Views: 2230

Answers (1)

Anastasiosyal
Anastasiosyal

Reputation: 6626

This is an old question but still deserves an answer as a point of reference, what you're after I believe is the function KeepLastValue

Takes one metric or a wildcard seriesList, and optionally a limit to the number of ‘None’ values to skip over. Continues the line with the last received value when gaps (‘None’ values) appear in your data, rather than breaking your line.

This would make your function 

 sumSeries(keepLastValue(server*.InboundCount))

This will work ok if you have a single null datapoint here and there. If you have multiple consecutive null data points you can specify how far back before a null breaks your data. For example, the following will look back up to 10 values before the sumSeries breaks:

 sumSeries(keepLastValue(server*.InboundCount, 10))

I'm sure you've since solved your problems, but I hope this helps someone.

Upvotes: 5

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