The ratio of object size to rds file size depends on the object. Some variation is due to how header information is stored in memory and in the file but I suspect most is due to how compression works (e.g., a vector of repeated values can be compressed into a smaller file than a bunch of random bytes).
f <- function (data, ...) { force(data) tf <- tempfile() on.exit(unlink(tf)) save(data, file = tf) c(`obj/file size` = as.numeric(object.size(data)/file.size(tf))) } > f(rep(0,1e6)) obj/file size 1021.456 > f(rep(0,1e6), compress=FALSE) obj/file size 0.9999986 > f(rep(89.7,1e6)) obj/file size 682.6555 > f(log(1:1e6)) obj/file size 1.309126 > f(vector("list",1e6)) obj/file size 2021.744 > f(as.list(log(1:1e6))) obj/file size 8.907579 > f(sample(as.raw(0:255),size=8e6,replace=TRUE)) obj/file size 0.9998433 > f(rep(as.raw(0:255),length=8e6)) obj/file size 254.5595 > f(as.character(1:1e6)) obj/file size 23.5567 Bill Dunlap TIBCO Software wdunlap tibco.com On Tue, Sep 18, 2018 at 8:28 AM, Joris Meys <jorism...@gmail.com> wrote: > Dear all, > > I tried to read in a 3.8Gb RDS file on a computer with 16Gb available > memory. To my astonishment, the memory footprint of R rises quickly to over > 13Gb and the attempt ends with an error that says "cannot allocate vector > of size 5.8Gb". > > I would expect that 3 times the memory would be enough to read in that > file, but apparently I was wrong. I checked the memory.limit() and that one > gave me a value of more than 13Gb. So I wondered if this was to be > expected, or if there could be an underlying reason why this file doesn't > want to open. > > Thank you in advance > Joris > > -- > Joris Meys > Statistical consultant > > Department of Data Analysis and Mathematical Modelling > Ghent University > Coupure Links 653, B-9000 Gent (Belgium) > <https://maps.google.com/?q=Coupure+links+653,%C2%A0B- > 9000+Gent,%C2%A0Belgium&entry=gmail&source=g> > > ----------- > Biowiskundedagen 2017-2018 > http://www.biowiskundedagen.ugent.be/ > > ------------------------------- > Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel