[R] sqldf for Very Large Tab Delimited Files

jim holtman jholtman at gmail.com
Sat Feb 4 01:42:27 CET 2012

Exactly what does "crashed" mean?  What was the error message?  How
you tried to put:


at the end of the loop to free up and compact memory?  If you watch
the performance, does the R process seem to be growing in terms of the
amount of memory that is being used?  You can add:


before the above statements to see how much memory is being used.
This is just some more elementary debugging that you will have to
learn when using any system.

On Fri, Feb 3, 2012 at 3:22 PM, HC <hcatbr at yahoo.co.in> wrote:
> Bad news!
> The readLines command works fine upto a certain limit. Once a few files have
> been written the R program crashes.
> I used the following code:
> *************************
> iFile<-"Test.txt"
> con <- file(iFile, "r")
> N<-1250000;
> iLoop<-1
> while(length(Lines <- readLines(con, n = N)) > 0 & iLoop<41) {
> oFile<-paste("Split_",iLoop,".txt",sep="")
>  write.table(Lines, oFile, sep = "\t", quote = FALSE, col.names= FALSE,
> row.names = FALSE)
>  iLoop<-iLoop+1
> }
> close(con)
> ********************
> With above N=1.25 million, it wrote 28 files of about 57 mb each. That is a
> total of about 1.6 GB and then crashed.
> I tried with other values on N and it crashes at about the same place in
> terms of total size output, i.e., about 1.6 GB.
> Is this due to any limitation of Windows 7, in terms of not having the
> pointer after this size?
> Your insight would be very helpful.
> Thank you.
> HC
> --
> View this message in context: http://r.789695.n4.nabble.com/sqldf-for-Very-Large-Tab-Delimited-Files-tp4350555p4355679.html
> Sent from the R help mailing list archive at Nabble.com.
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Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.

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