[gdal-dev] Closing connection in Python gdal (too many clients already)

[Even Rouault]

On Tuesday 02 August 2016 10:28:09 Yves Jacolin wrote:
> Bonjour Even,
> 
> On Tuesday, August 02, 2016 9:42:56 Even Rouault wrote:
> > Salut Yves,
> > 
> > > I am using gdal 2.1.1 in python.
> > > 
> > > When I import several layers into postgis I get a FATAL error : 'sorry,
> > > too
> > > many clients already'. It seems I don't close the connection after each
> > > import.
> > > 
> > > I open the connection with dstDS = gdal.OpenEx(connectionString). how
> > > can
> > > I
> > > close the connexion? I can't find any method
> > 
> > You just need to drop any reference to the dataset, so, assuming it is not
> > assigned to another variable, with dstDS = None or del dstDS.
> > 
> > See the "Saving and closing datasets/datasources" section at
> > https://trac.osgeo.org/gdal/wiki/PythonGotchas
> > 
> > Note: assuming you import layers from the same database, it will be (a
> > tiny
> > bit) more efficient if you re-use the same dataset object.
> 
> I tried both `del dstDS` and `dstDS = None`, but I still have the problem. I
> tried also to open just one connexion (see code below), but the problem is
> still there. I guess this is an other issue. Could the OGR import is still
> active when I import another file?
> 
> 
> dstDS = gdal.OpenEx(connectionString)
> 
> for id in idList:
> 
>     srcDS = gdal.OpenEx('/tmp/file_' + str(id) + '.geojson')
> 
>     gdal.VectorTranslate(
>      dstDS,
>      srcDS,
>      format = 'PostgreSQL',
>      layerName='myLayer'
>    )
>    del srcDS
> 
> del dstDS

Ah indeed, it is a different issue.

gdal.VectorTranslate() doesn't currently properly handle the situation where 
you pass a dstDS object but not specify accessMode to be 'append', 'update' or 
'overwrite'. So try adding accessMode = 'append' as an extra argument to 
gdal.VectorTranslate() (if the intent is to append to the same layer)
Could you open a ticket about that ? (in your situation where accessMode is 
not specified but dstDS is specified, accessMode = 'update' should be the 
default behaviour)

And you should also open dstDS with

dstDS = gdal.OpenEx(connectionString, gdal.OF_UPDATE | gdal.OF_VECTOR)

Even

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