Understanding the graphite response (datapoint) for a summarize query for last 24 hours

Question

Request:

http://example.com:8081/render?format=json&target=summarize(stats.development.com.xxx.operation.yyy.*.*.rate, "24hours", "sum", true)&from=-24hours&tz=UTC

Response:

[{"datapoints":[[0.1,1386198900]],"target":"summarize(stats.development.com.xxx.operation.yyy.5.4.rate, "24hours", "sum", true)"}]

What I wanted was the summary of last 24hours for the stat provided in query.

• Can you please interpret "datapoint" for me?
• What does "0.1" mean? What is its logarithmic scale?
• What does 1386198900 mean?

Answer 1

[{
  "datapoints" : 
              [[0.1,1386198900]], 
  "target":
              "summarize(stats.development.com.xxx.operation.yyy.5.4.rate, "24hours", "sum", true)"
}]

Here, datapoints sent to the metric stats.development.com.xxx.operation.yyy.5.4.rate, when numerically summed on a 24 hour basis, is 0.1 for the epoch 1386198900, which is the system's way of saying Wed, 04 Dec 2013 23:15:00 GMT. The logarithmic scale is not involved here.

Consider the following example-

You create a metric- website.about-us-page.hits and start sending data every 10 seconds-

1386198900: 3
1386198910: 23
1386198920: 12
1386198930: 1
1386198940: 0
1386198950: 180
1386198960: 12

This URL API request to graphite- target=summarize(stats.website.about-us-page.hits, "20seconds", "sum", true) will return something like-

[{
  "datapoints" : 
              [[26,1386198900]], // sum of first two points
              [[13,1386198920]], // sum of next two points
              [[180,1386198940]],
              [[12,1386198960]], 
  "target":
              "summarize(stats.website.about-us-page.hits, "20seconds", "sum", true)"
}]

summarize() basically helps you see the data in different granularity. Like in cases when you need to know day-wise or hour-wise traffic, rather than on a 10s basis.