[GRASSLIST:10155] Re: sqlite driver - remarks and questions

[Maciek Sieczka]

Hi,

An update regarding this post I sent few weeks ago.

On Tue, 22 Nov 2005 09:38:36 +0100
Maciek Sieczka <werchowyna at epf.pl> wrote:

> Grass 6.1 CVS 2005-11-16 built with sqlite 3.0.8-3, Ubuntu Hoary. 
> 
> Using the CONTOURL.shp from VMAP0 dataset:
> 
> maciek at sorbus:~$ ogrinfo -al -so CONTOURL.shp
> INFO: Open of 'CONTOURL.shp' using driver `ESRI Shapefile' successful.
> 
> Layer name: CONTOURL
> Geometry: Line String
> Feature Count: 173863
> Extent: (-31.252195, 30.000000) - (179.999420, 81.845779)
> Layer SRS WKT:
> (unknown)
> F_CODEDESC: String (50.0)
> ID: Real (11.0)
> HQC: Integer (6.0)
> F_CODE: String (5.0)
> TILE_ID: Integer (6.0)
> EDG_ID: Real (11.0)
> HQCDESC: String (50.0)
> ZV2DESC: String (50.0)
> ZV2: Integer (6.0)

<snip>

> 3. Exporting from sqlite back to shapefile with v.out.ogr is extremely
> fast when comapared to dbf - about 60 (sixty) times faster, wow!
> 
> 4. But, it fails to complete! At about 80% all my RAM (1GB) and swap
> (1GB) was eaten by sqlite process, which freezed my machine
> completely, had to power-off. Memory leak? Can be fixed?



Today I re-tried this with newer Grass 6.1 CVS, newer system (Ubuntu
Breezy) and sqlite 3.3.2, on the same machine. This time v.out.ogr
using sqlite performed much better. I don't know what is the reason
that now it works. Couple of things changed in my setup. Here's a
summary of what I recall that changed between the two scenarios:



SCENARIO 1, 22 Nov 2005:

Ubuntu 5.04 Hoary
Grass 6.1 CVS 2005-11-16
Sqlite 3.0.8

Symptoms: v.out.ogr failed to export a 173863 vector lines layer. At
'80%' system became was completely non responsive. There wasn't any
progress. Had to reboot.



SCENARIO 2, 05 Feb 2006:

Ubuntu 5.10 Breezy
Grass 6.1 CVS 2006-02-01
Sqlite 3.3.2

Symptoms: v.out.ogr managed to export a 173863 vector lines
layer. The 100% was achieved within about 5 minutes, memory use
remained fairly small until then. However, before the whole export was
accomplished it took 90 minutes more, while memory and swap were used
100% all that time. What's nice though, is that the system remained
responsive even then, only it was slow (considering 100% swap and
memory use it was a rocket though ;)).

Maciek

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