[Qgis-developer] SpatiaLite very slow with QGIS 1.7

[MORREALE Jean Roc]

Le 17/03/2011 19:47, a.furieri at lqt.it a écrit :
> On Thu, 17 Mar 2011 18:48:51 +0100, MORREALE Jean Roc wrote
>> Ticket #3002 may be linked, it is reproducible on windows/linux.
>>
>
> Hi Jean Roc,
>
> ticket #3002 isn't related at all to SpatiaLite
> and/or to the QGIS own SpatiaLite data provider.
>
> I've just attempted to save a (quite small sized)
> Shapefile as a SQLite DB following the procedure
> reported on ticket #3002.
>
> Yes, I can confirm, you are perfectly right: the
> export process is incredibly slow (>  10 minutes)
> and strongly inefficient (spatialite_gui performs
> the same identical task just in few seconds).
>
> Anyway, at the end of the process a basic SQLite
> DB was generated.
> Please note well: this is *not* at all a SpatiaLite
> own DB; this one is an OGR/FDO own DB (a completely
> different thing, using an independent code base).

Sorry for the mistake, I didn't knew there was a difference in the ouput.

> So for sure this issue is entirely caused by OGR,
> and has absolutely nothing to do with SpatiaLite.
>
> Just as a working hypothesis: during this painful
> export I noticed a very low CPU activity, and an
> impressively huge disk traffic.
> This is exactly what I'm expecting from a badly
> implemented process attempting to perform lots and
> lots of SQL INSERTs without declaring a corresponding
> BEGIN and COMMIT ... and such a condition notoriously
> is a real "performance killer" for any transactional
> DBMS. my 2 cents :-)

Can you confirm that it is due to OGR ? ogr2ogr with SPATIALITE=yes is 
faster than QGIS 'save as'