[gdal-dev] Default page size of the OAPIF driver

[Even Rouault]

Hi Jukka,

yes it would make sense for the driver to use a larger page size. You 
can file an issue about that

Actually we could reuse the same logic as the QGIS OAPIF provider that 
determines the page size from the limit.schema.maximum and 
limit.schema.default values of the /api response:

     if ( apiRequest.defaultLimit() > 0 && apiRequest.maxLimit() > 0 )
     {
       // Use the default, but if it is below 1000, aim for 1000
       // but clamp to the maximum limit
       mShared->mPageSize = std::min( std::max( 1000, 
apiRequest.defaultLimit() ), apiRequest.maxLimit() );
     }
     else if ( apiRequest.defaultLimit() > 0 )
       mShared->mPageSize = std::max( 1000, apiRequest.defaultLimit() );
     else if ( apiRequest.maxLimit() > 0 )
       mShared->mPageSize = apiRequest.maxLimit();
     else
       mShared->mPageSize = 100; // fallback to arbitrary page size


Even

Le 06/10/2023 à 16:39, Rahkonen Jukka via gdal-dev a écrit :
>
> Hi,
>
> The OAPIF driver is using page size of 10 features by default 
> https://gdal.org/drivers/vector/oapif.html#open-options.
>
> “PAGE_SIZE=<integer>: Defaults to 10. Number of features to retrieve 
> per request. Minimum is 1, maximum 10000.”
>
> I know that 10 is the default page size (“limit”) also in the standard 
> but I think that this is too small page size, both for the users and 
> especially for the service providers. Most users run GDAL utilities 
> with the defaults. The buildings collection in our OGC API Features 
> service has about 5 million features, which means that GDAL users are 
> fetching the data by sending half a million request. That is much 
> slower for the users than making 500 request, 10000 features each. And 
> think about our log files.
>
> The better default page size would be the biggest that the OAPIF 
> server supports. By the standard the maximum is 10000 but service 
> providers may use bigger or smaller maximum page sizes. By the 
> standard the server can always return less features than client is 
> asking with “limit=” and the client must be prepared to follow the 
> next links.
>
> My suggestion for the new page size default is 10000. If that feels 
> too big for some reason, then would 1000 feel better?
>
> -Jukka Rahkonen-
>
>
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