[gdal-dev] Can I leave OGR_INTERLEAVED_READING=YES on all the time?

[Even Rouault]

Le jeudi 23 mai 2013 11:01:46, Ian Turton a écrit :
> I'm developing an application that wraps OGR for feature ingest which works
> fine. With the new OSM driver all is good until a user tries to open a
> large file which hangs unless OGR_INTERLEAVED_READING=YES is set (then all
> is fine again).
> 
> However I don't really want users to have to decide if they have a large
> file or not and then mess around with environment variables, so is there
> any downside to setting this on in my code and leaving it on all the time?

No, no downside at all. You can always set OGR_INTERLEAVED_READING=YES 
provided that you actually use the layer interleaved reading pattern 
documented in the OSM driver documentation page.

> 
> if not what is the size break point at which I should turn it on?

Standard access pattern works while the OSM layers don't store more than 
100,000 features each. Above that threshold, you must use the interleaved 
reading pattern.

> 
> cheers
> 
> Ian

-- 
Geospatial professional services
http://even.rouault.free.fr/services.html