Bubble Charts input data structure [lacking documentation]

[splunk_zen]

From the latest docs, this is the simplest prerequisite to build a bubble chart,

"1. A single series structure that contains 3 columns. The first column (column 0) contains the values to be plotted on the x-axis. The second column (column 1) contains the values to be plotted on the y-axis. And the third column (column 2) contains the values to be plotted on the z-axis."

then why does the bubble chart fail to draw anything

(it originally was charting some nonsense bubbles when I was incorrectly feeding the _time field to the y axis)

when I build a search which feeds it the following table?

_time category count
7/4/12 1:00:00.291 PM TIMEOUT 10
7/4/12 4:00:00.294 PM HIT_MAX_REQ_LIMIT 3
7/4/12 1:00:00.296 PM ORA_EXCEPTIONS 1
7/4/12 4:00:00.296 PM ORA_EXCEPTIONS 0
7/4/12 1:00:00.300 PM HIT_MAX_REQ_LIMIT 2
7/4/12 4:00:00.291 PM HIT_MAX_REQ_LIMIT 1

This is my simple XML content,

  <option name="charting.chart">bubble</option>
  <earliestTime>-48h@h</earliestTime>
  <latestTime>now</latestTime>

How should I use them ?

Splunk devs, please further improve the bubble charts documentation with an example.

[mattness · Accepted solution]

I've consulted Splunk's expert on chart visualization issues and as it turns out when you've selected the "bubble" chart type in simple XML, Splunk will by default expect the y-axis to be a numeric value. This is (probably) why you're running into trouble.

You should be able to override this by changing the y-axis parameter in the simple XML for the chart. Try adding this line to the bubble chart XML and see if it doesn't solve your problem:

<option name="charting.axisY">category</option>

If it does I'll get the docs updated so they make this issue more clear.

(Note: The use of "category" here is not a reference to your "category" field, but rather an indication that you want the y-axis to display categorical values--strings, as opposed to numbers or timestamps. For more info see the topic on charting library axis parameters.)

[mattness]

The bubbles are the same color because you've set this up as a single series bubble chart. To get different colors, you'd need to configure the chart to handle multiple series. This would utilize a four-column table, where the first column would be the series (in your case, most likely the "category" field), and then the other three would be the x, y, and z axes respectively.

I'll look into the zero value issue.

Have you considered going with a stacked column chart instead? It seems like that would do a better job of expressing what you're trying to express here.

[splunk_zen]

Also,
I expected a bubble to not be charted when the y axis value has a corresponding z axis 0 value.
I tried both the following lines but the 0 value bubbles kept being drawn,
0
false

[splunk_zen]

mattness,
category
did indeed get the bubble chart closer to what I need.
https://dl.dropbox.com/u/927023/bubble2.PNG

However, why are all the bubbles the same color (when there are several diferent y axis metrics)?

[splunk_zen]

I do appreciate it. Thank you.
I will try it tomorrow as soon as I arrive to work.

Could you please take a look in my initial question http://splunk-base.splunk.com/answers/52300/search-generate-a-time-causes-count-collums-table and clarify if I indeed need to transform the data (or if there is a simpler way) into the aforementioned table ?

[splunk_zen]

For the record,
this doubt is related to my initial question,
http://splunk-base.splunk.com/answers/52300/search-generate-a-time-causes-count-collums-table