[rrd-users] Re: Request for Enhancement (grapher)

[Tobias Oetiker]

Today Owen DeLong wrote:

 |
 | I have a set of RRAs where I am gathering relatively high resolution
 | (.01 degree 5 second interval) temperature data.  In doing my analysis
 | of the data, I've found that the MIN and MAX consolidation functions
 | are quite useful over larger consolidation periods, while the AVERAGE
 | is very useful at high resolution.  I'd like to have the ability to
 | generate composite graphs which display the AVERAGE at one resolution
 | while simultaneously displaying the MIN/MAX at a much broader
 | consolidation.
 |
 | It would be nice if the grapher could support something like:
 |
 | DEF:min:temperature.rrd:MIN:3600
 | DEF:avg:temperature.rrd:AVERAGE
 | DEF:max:temperature.rrd:MAX:3600
 |
 | Then, I could graph something like (background is black):
 |
 | AREA:max#ff0000
 | AREA:min#000000
 | LINE3:avg#800000
 |
 | This would give me the high resolution average superimposed as a line
 | over the stripe stretching from the hourly minimum to the hourly
 | maximum.
 | I can probably implement this, but I wanted to ask about the following
 | before I did so...
 |
 | 	1.	Has anyone already accomplished this so I don't have to?
 |
 | 	2.	Do enough people see value to this capability to make it
 | 		worth changing the syntax so that this capability could
 | 		get rolled into a future release if I do make it work?
 |
 | 	3.	Does anyone have a suggestion on a better way to implement
 | 		the syntax.  I figured by making the :step optional at
 | 		the end of the DEF, it would remain compatible with
 | 		existing scripts, but also allow this flexibility.
 |
 | Another enhancement I'm considering is modifying the RPN capabilities
 | to support PREV[variable] for retrieving the previous value of another
 | variable.  If anyone has any ideas or thoughts on the usefulness of
 | this, I'd like to hear them.
 |
 | Finally, what do people think of having an RPN function called SUM
 | or SIGMA, which would be of the form:
 |
 | 	CDEF:foo=sourcevar,SUM
 |
 | Which would result in foo containing a "Total to date" for each
 | iteration,
 | and would allow a GPRINT of foo MAX with "Total: %lf" to print a total
 | of the
 | data in sourcevar.

the explicit resolution selection is something I have had on my
plate for some time, so I find it definitly a good thing ...

as for PREV, make sure you read the docs for rrdtool 1.1.x first
... alex and jake have been attacking the RPN machine
severely in the cvs copy of rrdtl already. :-)


you can get the latest snapshot from the pub/beta directory of the
rrdtool website ... where you download the regular rrdtool as well
...

make your patch relative to the 1.1.x beta
best would be if you first wrote a pod documentation on the new
functionality and its interface so that you can post it to
rrd-developers for review

cheers
tobi

 |
 | Thanks,
 |
 | Owen
 |
 |

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