df.to_gbq(data, dataset, chunksize=10000, verbose=False, reauth=False, if_exists='append', private_key=private_key)

Problem description

We only insert DataFrame one time It seems is in insert because we also see duplicates in Bigquery WebUIConsole can be related with https://github.com/pandas-dev/pandas/issues/5840?

pandas==0.19.2

Comment From: jreback

w/o a reproducible example this is not useful

if you would like to add an example great