[rrd-users] RRD::update failing on first update every time?

[Jo Rhett]

I have a statistical data source giving me numbers that are exactly 300 seconds apart, with multiple intervals at once.  (ie data in 5 minute windows delivered hourly, etc)

Data which is exactly 300 seconds apart should make RRD happy, but RRD is always rejecting the very first update.   Why?

       RRD filename is /rrd/vlan-0.0/queue-1.rrd
        getLatestRRDTimestamp( /rrd/vlan-0.0/queue-1.rrd ):
                rrd start = 1281393300, step = 300
		(steps through data to find the last defined value)
        Exiting getLatestRRDTimestamp( /rrd/vlan-0.0/queue-1.rrd ) with timestamp 1281406200
        insert into /rrd/vlan-0.0/queue-1.rrd values 1281406473, 3420012071625, 3420012071625
ERROR while updating /rrd/vlan-0.0/queue-1.rrd: illegal attempt to update using time 1281406473 when last update time is 1281406473 (minimum one second step)
        insert into /rrd/vlan-0.0/queue-1.rrd values 1281406773, 3420061076791, 3420061076791
        insert into /rrd/vlan-0.0/queue-1.rrd values 1281407073, 3420108690075, 3420108690075
        insert into /rrd/vlan-0.0/queue-1.rrd values 1281407373, 3420860926634, 3420860926634

Why is it failing on the first update every time?  And no, I'm not doing an update at any other time, there's only one place in the code where update() is called, and it outputs the debug message you see here...

-- 
Jo Rhett
Net Consonance : consonant endings by net philanthropy, open source and other randomness