You should really take this up with RStudio. Calling object.size on every top level assignment as they appear to do is a bad idea, even without ALTREP. object.size is only a cheap operation for simple atomic vectors. For anything with recursive sturcture it needs to walk the object, so the effort is proprtional to object size:
> x <- rep("A", 1e8) > system.time(object.size(x)) user system elapsed 1.222 0.624 1.850 > x <- rep(list(1), 1e8) > system.time(object.size(x)) user system elapsed 1.247 0.022 1.273 The current help for object.size says Provides an estimate of the memory that is being used to store an R object. If this is interpreted as the current memory use, which could change in the ALTREP context (or for environments, though there the changes are ignored), then we could define object.size for ALTREP objects to avoid any ALTREP-specific computation. I'm not convinced yet that this is a good idea, but it even if we do change this at the R level, RStudio would still be well-advised to have another look at what they are doing. Best, luke On Tue, 15 Jan 2019, Travers Ching wrote: > > Below is a toy alt-rep string example, that generates N random strings: > > https://gist.github.com/traversc/a48a504eb062554f2d6ff8043ca16f9c > > example: > `x <- altrandomStrings(1e8)` > `head(x)` > [1] "2PN0bdwPY7CA8M06zVKEkhHgZVgtV1" "5PN2qmWqBlQ9wQj99nsQzldVI5ZuGX" ... > `object.size(1e8)` > > Object.size will call the `set_altstring_Elt_method` for every single > element, materializing (slowly) every element of the vector. This is > a problem mostly in R-studio since object.size is called > automatically, defeating the purpose of alt-rep entirely. > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > -- Luke Tierney Ralph E. Wareham Professor of Mathematical Sciences University of Iowa Phone: 319-335-3386 Department of Statistics and Fax: 319-335-3017 Actuarial Science 241 Schaeffer Hall email: luke-tier...@uiowa.edu Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel