Folks, Some folks have experienced poor performance with some GDAL drivers, particularly on network disks, due to the high cost of fseek() and ftell() operations. I have reworked the VSIL implementation used for IO on non-win32 operating systems to try and keep track of the current file offset, and whether file access is already at the end of file in order to short circuit some fseek() and ftell() operations.
The one serious concern I have about this is that we will never know if another process and opened and extended a file while we are accessing it. For most drivers this would cost lots of other problems anyways, but there could be places VSIL IO is used that it would be quite acceptable. The change is: http://trac.osgeo.org/gdal/changeset/17402 I'd appreciate people letting me know if they believe this change is causing them problems. We could potentially do something similar for the win32 implementation but for now the painpoint happened to be on linux. Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, [email protected] light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Programmer for Rent _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
