[Gvsig_english] (no subject)

[Cèsar Ordiñana]

Hi Holger,

As Fran has already pointed at, gvSIG 2.0 will provide a new 
implementation for the data access layer (dal), which avoids the need 
for random position access, so in the case of a database, data is only 
loaded when requested.

Hopefully, gvSIG 2.0 will have less memory problems depending on the 
size of a database table, but we still have to perform more testing to 
stress those cases.

Regards,

-- 
Cèsar Ordiñana Navarro
Arquitecto Software gvSIG
DiSiD Technologies SL  http://www.disid.com




Francisco José Peñarrubia escribió:
> Hi Holger.
>
> I think this behaviour is different in gvSIG 2.0. The reason is in 2.0 
> release, the random access is not needed like in 1.9 release.
>
> So, you only have 2 options, wait for 2.0 release, or use a where clause 
> in the layer creation. I think you can define your "working area" from 
> the dialog of postgis layer loading (in 1.9).
>
> Best regards.
>
> Fran.
>
> Holger Jaekel escribió:
>   
>> Dear gvSIG developers,
>>
>> when we add a layer from PostGIS to gvSIG 1.9, we can see that two ressource intensive operations are performed on the database:
>>
>> 1. A database cursor is created for this layer in PostGisDriver.setData(IConnection, DBLayerDefinition), which selects all objects from the table
>> 2. A Hashtable is filled in PostGisDriver.doRelateID_FID(), which contains one entry for each object from our layer.
>>
>> We have to work with layers that contain more than 10,000,000 polygons. In that case, the cursor allocates many ressources on the database side, so this solution does not scale very well for many users. In the second step, gvSIG tries to create a Hashtable with >10,000,000 entries, which will create an OutOfMemoryException. This will also happen if we use "maxScale" for this layer.
>>
>> Any hints how gvSIG can handle large layers?
>>
>> Thank you very much for your help,
>>   Holger
>>
>>   
>>     
>
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