[R] reading large data

HENRIKSON, JEFFREY JEFHEN at SAFECO.com
Fri Jul 2 18:37:46 CEST 2004


Hello,

I have trouble using read.table for flat files of larger than about
300MB on windows 2000.  Any ideas of how to file a bug report?  Is it a
known issue?  I have three cuts of data, a 1%, 10% and 100% sample in
flat text files.  The 100% sample is about 350MB.  When I read the 1%
and 10% files, besides being slow, everything works.  RAM footprint
appears to increase approximately 2x of text file size when loaded.  I
have 1.5GB of ram on my machine.  The 10% file takes < 1.5 minutes to
load.  So the 100% file I would think would load in < 15 minutes.  But
it grinds for about 15 mins and then seg faults instead.  I don't think
there's really very special about my data.  Just several columns by ~5M
rows.

The same thing happens when I read the 100% sample in from an RDBMS with
RODBC.

For the time being I have worked around by feeding in small cross
sections 100% from the RDBMS, and storing a 10% whole sample in RAM.
But in the future it would be nice if I could just use the RAM in my
box.


Jeff Henrikson




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