[rrd-users] HRULE being parsed incorrectly on command line?

Kevin Day toasty at dragondata.com
Sat May 14 18:49:33 CEST 2011

On May 14, 2011, at 11:30 AM, Jaime Lozano wrote:

>> rrdtool graph --imgformat PNG out.png DEF:ds0=in.rrd:x:AVERAGE CDEF:unknown=ds0,UN,INF,UNKN,IF VDEF:ds0max=ds0,MAXIMUM VDEF:ds0min=ds0,MINIMUM DEF:ds1=in.rrd:y:AVERAGE HRULE:ds1
> In http://oss.oetiker.ch/rrdtool/doc/rrdgraph_graph.en.html it says about VRULE:
> "It is an error to use vnames from DEF or CDEF here" and then "HRULE
> acts much like LINE except that will have no effect on the scale of
> the graph" so I think you are wrong, and you cannot do that. If HRULE
> is a straight line, why trying to use a non constant value?

See, I interpreted that same sentence as though it meant "You can treat an HRULE as a LINE, it just doesn't adjust the y scale to make it fit".  Partially because both LINE and HRULE say they take a "value", and values "can be generated by DEF, VDEF, and CDEF". 

In either case, the error message being produced is wrong, it refers to the wrong named value. Depending on what you have before trying to use an HRULE the vname printed changes to other seemingly random vnames or is blank.


-- Kevin

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