[Qgis-developer] Trouble with PostGis plugin

[Sandro Santilli]

On Fri, Oct 10, 2014 at 03:56:05AM -0700, walter.nordmann wrote:
> Chris Crook wrote
> > Hi Walter
> > 
> > When you connect to the PostGis database make sure that you have selected
> > the "Use estimated metadata" option - this optimises the connection for
> > large datasets - see attached screenshot.  This should greatly improve the
> > connection times for postigs.  (If you are already doing this then may
> > need to look further!)
> 
> "Use estimated metadata" is true and i see (in wireshark!) qgis is only
> fetching 100 samples to get the geometry. But even that needs a very long
> time. 
> 
> I think, Postgis is doing a sequential search but i'm no shure about that.
> But why does Qgis check the geometry? it is allready known and should not be
> necessary.

Can you send the whole query ?
I think there's a class of such issues with big tables that need be
addressed (and secured with some automated testcase).

> This part of Qgis is for me like a Black Box: select your data and wait. No
> loggin, no infos, nothing. Just wait.

You can open some of the box by connecting to the database
and looking at the pg_stat_activity table.

It would contain querying being processed.

> That is very frustrating in the developement-phase of a map. Killed the
> Qgis-Process dozend times a day, loaded my last save and started again. :(

I feel your pain.
If you can, please test this issue with the current master branch so if
something has to be fixed it has a chance to be in time for version 2.6 
(due in 2 weeks).

--strk;

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