[collectd] plugin "Aggregation" dont want to "sum()"

[Gerardo Herzig]

Hi all. Im having a hard time trying to make this plugin work.

The idea is to sum() all the "errors" counters for a switch, collected via snmp plugin.
The individual error (for each port) of the switch is getting fine, but the aggregation is returning NANs all the time:

trunks:/opt/collectd/var/lib/collectd/switch.157.92.152.109/snmp # rrdtool fetch if_rx_errors-31.rrd AVERAGE | tail
1432761600: 2,1131720430e+00
1432761660: 8,4166666667e-01
1432761720: 1,1236559140e+00
1432761780: 6,9892473118e-01
1432761840: 5,9641577061e-02
1432761900: 1,0177777778e+00
1432761960: 1,1397849462e-01
1432762020: 2,0060483871e-01
1432762080: 9,9395161290e-02
1432762140: -nan


trunks:/opt/collectd/var/lib/collectd/switch.157.92.152.109/aggregation-snmp-sum # rrdtool fetch if_rx_errors.rrd AVERAGE | tail
1432761540: -nan
1432761610: -nan
1432761680: -nan
1432761750: -nan
1432761820: -nan
1432761890: -nan
1432761960: -nan
1432762030: -nan
1432762100: -nan
1432762170: -nan

The collectd.conf look like this:

<Plugin "aggregation">
  <Aggregation>
    Plugin "snmp"
    Type "if_rx_errors"
    CalculateSum true
    GroupBy "Host"
  </Aggregation>
</Plugin>

<Plugin snmp>
  <Data "IfInErrors">
    Type "if_rx_errors"
    Table true
    Values "1.3.6.1.2.1.2.2.1.14"
  </Data>

  <Host "switch.157.92.152.109">
      Address "157.92.152.109"
      Version 2
      Community "public"
      Collect "IfInErrors" 
    Interval 30
  </Host>
</Plugin>

The "if_rx_errors" defined as:

trunks:/opt/collectd/share/collectd # grep if_rx_errors types.db 
if_rx_errors            value:DERIVE:0:U

So im missing something....just dont know what is it :)

Some help would be great.
Thanks!

Gerardo