[datatable-help] Random segfaults

[Timothée Carayol]

Hi --

I have been having many unreproducible bugs with R 2.14, data.table
1.7.4 and ubuntu 64 bits about 10 days ago. Data was getting
corrupted, and then R crashed. I had to go back to data.frame for the
bits of code affected. I was doing a lot of rather unsafe
manipulations with row names, rbind and cbinds.
I didn't file a report, nor signal it, as it was occurring seemingly
at random, and I was doing operations which aren't really what
data.table was made for (tons of little manipulations on small data);
still I guess I should now signal that 2.14 didn't fix everything for
me. I do not know whether bugs subsist on post-1.7.4 versions.

t

On Wed, Dec 14, 2011 at 5:31 PM, Matthew Dowle <mdowle at mdowle.plus.com> wrote:
>
> Maybe, worth a try. Are you loading any data.table objects from disk?
>
>> 64 bit 2.12.1 linux.
>>
>> Is there an option I can set in my session in order to work around the
>> truelength issue? I don't care if I lose some of the over-allocation
>> niceties if it stops things from crashing. Looking at the truelength
>> help, would just doing:
>>
>> options(datatable.alloc=quote(1000))
>>
>> stop this? I never have more than about 50 columns at a time.
>>
>> On 14 December 2011 11:43, Matthew Dowle <mdowle at mdowle.plus.com> wrote:
>>>
>>> You're R < 2.14.0, right?  I'm really struggling in R < 2.14.0 to make
>>> over-allocation work because R only started to initialize truelength to
>>> 0
>>> in R 2.14.0+. Before that it's unitialized (random). Trouble is my
>>> attempts in R < 2.14.0 to work around that work fine for me in linux
>>> 32bit
>>> when I test in R 2.13.2, and I even test in 2.12.0 too. I test on 64bit
>>> too but just 2.14.0.  CRAN is also showing errors on 2.13.2 (old-rel)
>>> for
>>> both mac and windows.
>>>
>>> So, this is a pre-2.14.0 (only) problem that I'll continue to try and
>>> fix.
>>>
>>> Are you 64bit pre-2.14.0? Which OS?  If you are 64bit linux then it adds
>>> weight to me installing pre-2.14.0 on my 64bit instance in an effort to
>>> reproduce.
>>>
>>>
>>>> This will be a crappy help request because I can't seem to reproduce
>>>> it, but the past few days I've been getting a lot of segfaults.  The
>>>> only common thing between every crash is that it happens when I do
>>>>
>>>> DT[, z := x]
>>>>
>>>> where z was not a column that existed in DT before, and x is either an
>>>> existing column of DT or a separate variable, doesn't matter.  Beyond
>>>> that I can't reproduce a set of steps that gets R to crash.  This is
>>>> with the latest SVN version.
>>>>
>>>> Is there more information I can provide to help track this down?
>>>> _______________________________________________
>>>> datatable-help mailing list
>>>> datatable-help at lists.r-forge.r-project.org
>>>> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
>>>>
>>>
>>>
>>
>
>
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