object.size vs lobstr::obj_size
On 3/27/20 12:00, Hadley Wickham wrote:
On Fri, Mar 27, 2020 at 10:39 AM Herv? Pag?s <hpages at fredhutch.org
<mailto:hpages at fredhutch.org>> wrote:
Hi Tomas,
On 3/27/20 07:01, Tomas Kalibera wrote:
> they provide an over-approximation
They can also provide an "under-approximation" (to say the least) e.g.
on reference objects where the entire substance of the object is
ignored
which makes object.size() completely meaningless in that case:
? ?setRefClass("A", fields=c(stuff="ANY"))
? ?object.size(new("A", stuff=raw(0)))? ? ? # 680 bytes
? ?object.size(new("A", stuff=runif(1e8)))? # 680 bytes
Why wouldn't object.size() look at the content of environments?
As the author, I'm obviously biased, but I do like lobstr::obj_sizes()
which allows you to see the additional size occupied by one object given
any number of other objects. This is particularly important for
reference classes since individual objects appear quite large:
A <- setRefClass("A", fields=c(stuff="ANY"))
lobstr::obj_size(new("A", stuff=raw(0)))
#> 567,056 B
But the vast majority is shared across all instances of that class:
lobstr::obj_size(A)
#> 719,232 B
lobstr::obj_sizes(A, new("A", stuff=raw(0)))
#> * 719,232 B
#> * ? ? 720 B
lobstr::obj_sizes(A, new("A", stuff=runif(1e8)))
#> * ? ? 719,232 B
#> * 800,000,720 B
Nice. Can you clarify the situation with lobstr::obj_size vs pryr::object_size? I've heard of the latter before and use it sometimes but never heard of the former before seeing Stefan's post. Then I checked the authors of both and thought maybe they should talk to each other ;-) Thanks, H.
Hadley -- http://hadley.nz <https://urldefense.proofpoint.com/v2/url?u=http-3A__hadley.nz&d=DwMFaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=MX7Olw-dGRDfJNWEqIDTTTkaagVswOEqcRnxuRBAdjw&s=haVkOV6bEj7VnjT4Gn4iXzRqO7IOqDZUZuEeFPSHQuM&e=>
Herv? Pag?s Program in Computational Biology Division of Public Health Sciences Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N, M1-B514 P.O. Box 19024 Seattle, WA 98109-1024 E-mail: hpages at fredhutch.org Phone: (206) 667-5791 Fax: (206) 667-1319