[GRASS-user] v.clean process killed itselt!?

[Glynn Clements]

Nikos Alexandris wrote:

> Attempting to clean a very big vector map (after patching and before
> dissolving) ended without success. It's about all CORINE tiles to form
> the European-wide land cover map.
> 
> The process was running for 2 days now and killed itself for reasons I
> don't understand. The machine I currently work with has 4GB of RAM and
> 8GB of swap memory, not to mention the free hard disk space.
> 
> # the map is big!
> GRASS 6.4.svn (corine):/geo/grassdb/europe/corine/PERMANENT/vector > ls -lah corine

> -rw-r--r--   1 nik nik 1.9G 2009-01-06 10:01 coor

Ouch.

> -rw-r--r--   1 nik nik 647M 2009-01-06 09:59 topo

Ouch.

For vectors, you should assume that not only will you need to store
the entire map in memory, but the in-memory version may be
significantly larger than the underlying files due to the need to
store additional information related to the processing.

> # cleaning...
> GRASS 6.4.svn (corine):~ >  v.clean corine out=corine_clean tool=snap,break,rmdupl thresh=.01
> Killed

> -The "w" was pressed by me accidentally. But I assume that it has little
> to do with the process being killed.

Correct.

> -Additionally, I was watching from time to time the process's status via
> "top".
> 
> What on earth killed this "important" process?

It was most likely terminated due to excessive resource usage, either
for exceeding its own specified limits (see "ulimit -a") or for
depleting system-wide resources to the extent that the kernel killed
it to protect overall system integrity.

> How should on go about and clean this map?

On a 64-bit system with a lot of RAM. A 32-bit system limits each
process to a 4GiB address space, some of which is reserved.

-- 
Glynn Clements <glynn at gclements.plus.com>