[ncl-talk] NCL question [cannot create child process]

[Rick Brownrigg]

Hi,

Yes, you are definitely facing memory issues, and I don't understand enough
of your script to recommend a work around. The error is happening at this
line:

    #75:      files_1 = systemfunc("ls " + file_type + "_" + domain + "_" +
year + "-" + month + "*")

which as you likely know means that the system can't fork another bash
process to run the "ls" command. And it appears that it happens on the
third time through the loop over dimsizes(mm). We've seen this sort of
thing before, and it always means the system is terribly memory taxed, and
something sooner than later will raise a signal 12 -- just happens to be
the systemfunc() call in your case.

I see that after the loop over dimsizes(mm), you write a NetCDF file.
Again, I don't understand your script enough, so this might not make sense,
but perhaps you might write smaller NetCDF files each time through the
loop, and then use a post-processing step (perhaps the NCO or CDO
operators) to concatenate the files together?

Wish I had a better answer...
Rick


On Wed, Feb 27, 2019 at 4:50 PM lslrsgis at whu.edu.cn <lslrsgis at whu.edu.cn>
wrote:

>  Hi, everyone
>
>
> I am writing for a NCL question. When I executed a .ncl script (Ubuntu at PC)
> to extract monthly/daily records from WRF outputs, the program stopped
> after processing two month data. Information prompted out as bellow:
>
>
>
> *fatal:systemfunc: cannot create child process:[errno=12]*
>
> *fatal:["Execute.c":8637]:Execute: Error occurred at or near line 75 in
> file wrfout_postprocess_tzadjust.ncl*
>
>
>
> It seems be memory-out based on online search and ncl-talk achieves. While
> I have already released the memory using “delete” within each loop. What
> can I do?
>
>
>
> Any indications? Thanks in advance.
>
>
>
> Liang
>
>
>
> P.S. The script and log file are attached.
>
>
> The cmd within .ncl is written to list all wrfout files within one month.
>
> ls wrfout_d01_2015-01*
>
> ls wrfout_d01_2015-02*
>
> ls wrfout_d01_2015-03*
>
> ...
>
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