[rrd-developers] Weird resolution

[Jean-Michel Vourgère]

Hi

While investigating an issue with PREV(), I found myself unable to
explain the resolution in that case:
- An rrd file "esel.rrd" is created by "create.sh" and filled by "fill.py".

Data is available:
- Every 2 minutes for 12 hours
- Every 8 minutes for 48 hours
- ...

When I graph starting at "end-12h" or "end-11h", I expected a 2 minute
resolution. But what I get is more like a 8 minutes one.
See attached "graph.sh" and the resulting png.
Width is 720 pixels wide: One pixel per minute on a 12 hours period.
The resolution is ok for 10 hours (smooth curve), but 11 hours and 12
hours yield a stair effect.

Is that a bug?
-------------- next part --------------
A non-text attachment was scrubbed...
Name: create.sh
Type: application/x-shellscript
Size: 170 bytes
Desc: not available
URL: <http://lists.oetiker.ch/pipermail/rrd-developers/attachments/20150827/bb40e483/attachment.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: esel.rrd
Type: application/octet-stream
Size: 12728 bytes
Desc: not available
URL: <http://lists.oetiker.ch/pipermail/rrd-developers/attachments/20150827/bb40e483/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: fill.py
Type: text/x-python
Size: 343 bytes
Desc: not available
URL: <http://lists.oetiker.ch/pipermail/rrd-developers/attachments/20150827/bb40e483/attachment.py>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: graph.sh
Type: application/x-shellscript
Size: 577 bytes
Desc: not available
URL: <http://lists.oetiker.ch/pipermail/rrd-developers/attachments/20150827/bb40e483/attachment-0001.bin>