Unable to access ffdf file from .RData

Question

I loaded big data files (https://www.kaggle.com/c/avazu-ctr-prediction) using the read.csv.ff command from ff package using the following command:

 train = read.csv.ffdf(file="path to my big data files/train.csv",VERBOSE=TRUE)

then save it using the usual save workspace from RStudio. It created two files:

an .RData file and .ffData one which is a compressed file.

Everything worked fine but each time I restart my computer or close RStudio and open RStudio again, I'm unable to access ffdf objects from my workspace giving the error:

 >train[1,]

    file.access(filename, 0) == 0 is not TRUE

Or I can see the ffobject in the workspace I loaded.

What is this problem? how could I fix it?

Thanks in advance, HR

Answer 1

Use 'ffsave', not 'save', and then 'ffload' when you want to read it back in again. So, something like:

ffsave(train,file = 'mynamedtrainfile)