List size for large data.tables (#6609)

* List size for large data.tables

Fixes #6607

* Edits based on guidance from @MichaelChirico

* Explicitly list the size as a numeric instead of integer.

Modified NEWS and DESCRIPTION files to include details pertaining to the PR.

* Better phrasing of the bug fix.

Great suggestion by @ben-schwen!

* Update inst/tests/other.Rraw

* more specific about 2GiB size for "large"

---------

Co-authored-by: Benjamin Schwendinger <[email protected]>
Co-authored-by: Michael Chirico <[email protected]>

Author: 3 people

DESCRIPTION

@@ -97,5 +97,6 @@ Authors@R: c(
   person("Vincent", "Runge",       role="ctb"),
   person("Christian", "Wia",       role="ctb"),
   person("Elise", "Maigné",        role="ctb"),
-  person("Vincent", "Rocher",      role="ctb")
+  person("Vincent", "Rocher",      role="ctb"),
+  person("Vijay", "Lulla",         role="ctb")
   )

NEWS.md

@@ -105,6 +105,8 @@ rowwiseDT(
 
 10. `DT[1, on=NULL]` now works for returning the first row, [#6579](https://github.com/Rdatatable/data.table/issues/6579). Thanks to @Kodiologist for the report and @tdhock for the PR.
 
+11. `tables()` now returns the correct size for data.tables over 2GiB, [#6607](https://github.com/Rdatatable/data.table/issues/6607). Thanks to @vlulla for the report and the PR.
+
 ## NOTES
 
 1. Tests run again when some Suggests packages are missing, [#6411](https://github.com/Rdatatable/data.table/issues/6411). Thanks @aadler for the note and @MichaelChirico for the fix.

R/tables.R

@@ -5,7 +5,7 @@ type_size = function(DT) {
   # for speed and ram efficiency, a lower bound by not descending into character string lengths or list items
   # if a more accurate and higher estimate is needed then user can pass object.size or alternative to mb=
   # in case number of columns is very large (e.g. 1e6 columns) then we use a for() to avoid allocation of sapply()
-  ans = 0L
+  ans = 0.0
   lookup = c("raw"=1L, "integer"=4L, "double"=8L, "complex"=16L)
   for (i in seq_along(DT)) {
     col = DT[[i]]

inst/tests/other.Rraw

@@ -766,3 +766,10 @@ if (loaded[["nanotime"]]) {
   # respect dec=',' for nanotime, related to #6446, corresponding to tests 2281.*
   test(31, fwrite(data.table(as.nanotime(.POSIXct(0))), dec=',', sep=';'), output="1970-01-01T00:00:00,000000000Z")
 }
+
+# tables() with large environment #6607
+.e <- new.env() ## to not populate the .GlobalEnv
+.e[["DT"]] <- as.data.table(lapply(1:15,function(i) runif(20e6)))
+res <- tables(env=.e)
+test(32, res[, .(NAME,NROW,NCOL,MB)], data.table(NAME="DT",NROW=20000000L,NCOL=15L,MB=2288.0))
+rm(.e, res)