[rrd-users] Empty Graph, Database Contains Data

[Itai Zukerman]

I'm probably missing a command-line parameter somewhere, but I've been
looking at this for 2 hours and I still don't see what I'm doing
wrong.

$ rrdtool fetch --start 1227746280 --end 1227747780 php-pv.rrd AVERAGE
                             ct                   t                  tt

1227746340: 8.1154809062e+03 1.9715162243e+06 2.4293276604e+02
1227746400: 8.0776543748e+03 1.5803877059e+06 1.9564933489e+02
1227746460: 8.0904326041e+03 1.6353549845e+06 2.0213443020e+02
1227746520: 8.0782914134e+03 1.7629137584e+06 2.1822854217e+02
1227746580: 8.0591816950e+03 1.7647885736e+06 2.1897863089e+02
1227746640: 8.1015957290e+03 1.6930777712e+06 2.0898077710e+02
1227746700: 8.1513871708e+03 1.6469737358e+06 2.0204827735e+02
1227746760: 8.1197593991e+03 1.6821241763e+06 2.0716428820e+02
1227746820: 8.0650273687e+03 1.6296022002e+06 2.0205786363e+02
1227746880: 8.0476849282e+03 1.8130775286e+06 2.2529181308e+02
1227746940: 8.1828678593e+03 1.7075118117e+06 2.0866911712e+02
1227747000: 8.1380719128e+03 1.7851506955e+06 2.1935794063e+02
1227747060: 8.0535365129e+03 1.9853770209e+06 2.4652238401e+02
1227747120: 7.9661373187e+03 1.5854453295e+06 1.9902309816e+02
1227747180: 7.9710064674e+03 1.4997003071e+06 1.8814440977e+02
1227747240: 8.0238931448e+03 1.4386832970e+06 1.7929990729e+02
1227747300: 8.0514973543e+03 1.5171316011e+06 1.8842850396e+02
1227747360: 8.0059593977e+03 1.6214841288e+06 2.0253464303e+02
1227747420: 7.9704041801e+03 1.6780499179e+06 2.1053510964e+02
1227747480: 7.9419414952e+03 1.4431073794e+06 1.8170712794e+02
1227747540: 7.8772943668e+03 1.4465991672e+06 1.8364162870e+02
1227747600: 7.8409271612e+03 1.4532869521e+06 1.8534631456e+02
1227747660: 7.8928541771e+03 1.4963203023e+06 1.8957911406e+02
1227747720: 7.9219637411e+03 1.4822559079e+06 1.8710713105e+02
1227747780: 7.9287074930e+03 1.6040745963e+06 2.0231224291e+02
1227747840: 7.8802716627e+03 2.0004413573e+06 2.5385436479e+02

$ rrdtool graph ct.png --start 1227746280 --end 1227747780 'DEF:ctx=php-pv.rrd:ct:AVERAGE' LINE2:ctx:#333333
481x149

And then ct.png is empty.  Help, please?