[ESS-bugs] ess-mode 15.09-1 [elpa: 20151013.1025]; iESS Performance Degrades Quickly with Buffer Size

[Jason Morgan]

On Wed, Oct 14, 2015 at 10:55 AM, Martin Maechler
<maechler at stat.math.ethz.ch> wrote:
> Actually, I just tried myself, also with 15.09, and
> very embarrassingly:
>
>      Houston, we'got a problem !
>
> Try our old ESS internal (ess/etc/slow-long-output.R) :
>
> ###  Example modified from Paul Johnson's post to ESS-help, Nov.25, 2013
> op <- options("max.print")
>
> ##' construct (random) character vector of length n,  of about 10 characters each
> mkCh <- function(n) {
>     if(getOption("max.print") <= n) options(max.print = n + 1) ## <-
>     if(n == 10) stop("error's message with apostrophe - work's in developer mode")
>     N <- pmin(26,pmax(1, rpois(n, 10)))
>     cbind(vapply(N, function(m) paste(sample(letters, m), collapse=""), ""))
> }
>
> set.seed(1)
> y <- mkCh(9999)
> system.time(print(y))
>
> ## which in current ESS 15.09-1  took about 13 seconds for me,
> but only less 1.9 secondes in  ESS 14.09
>
> Or the *much* more extreme (for ESS 15.09-1):
>
> set.seed(23456)
> y <- mkCh(50000)
> system.time(print(y))
>
>
> ## which basically freezes emacs after printing an initial part
>
> --> so we are back at the very bad behavior Vitalie may
> remember  we had in Decemeber 2013
>
> ESS-core members: do look at
>
>   https://stat.ethz.ch/mailman/private/ess-core/2013/007622.html
>
>
> ----
>
> So indeed, Jason, we have a big problem, already in the release
> ESS 15.09.
>
> Thanks a lot for your report!
> Martin

Thanks, Martin. I'm glad (I guess?) it's not just me. Will this bug be
posted to GitHub, so I can watch it's status? I'm just getting into
development in emacs and I would be interested to see what the problem
is.

-- 
~ Jason Morgan

"Those who have had no share in the good fortunes of the mighty
 Often have a share in their misfortunes."
                -- Bertolt Brecht, "Der Kaukasische Kreidekreis"
                                    (The Caucasian Chalk Circle)