[Qgis-developer] Sample

[Nathan Woodrow]

Hey,

Yeah I'm thinking it might just be slow for something like shapefile where
is there no index on that column and it has to get each value to find
the unique
ones.  I'm not looking at the code, just guessing.

- Nathan


On Tue, Jul 15, 2014 at 4:09 PM, Jürgen E. <jef at norbit.de> wrote:

> Hi Nathan,
>
> On Tue, 15. Jul 2014 at 15:59:27 +1000, Nathan Woodrow wrote:
> > On Tue, Jul 15, 2014 at 3:57 PM, Jürgen E. <jef at norbit.de> wrote:
> > > On Tue, 15. Jul 2014 at 07:12:22 +0200, Paolo Cavallini wrote:
> > > > IMHO it should perform a quick LIMIT 10 query.
>
> > > Have you verified that is doesn't?  Because that's what it used to do.
>
> > Seems it calls uniqueValues so if that takes a long time it will block.
> > Depends on the provider I guess.
>
> Of course.  LIMIT 10 probably is meant for the postgres provider - and
> that's
> what it does already.  The spatialite provider does too.   The oracle
> provider
> limits with "rownum" and mssql uses "top".  So unless there's something
> preventing the provider's uniqueValues to kick in, it's already there.
>
>
> Jürgen
>
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