Saulteau Don <sault.don <at> gmail.com> writes: > > On 2/17/2014 11:39 AM, Even Rouault wrote: > > Le lundi 17 février 2014 16:31:55, Jukka Rahkonen a écrit : > >> Jukka Rahkonen <jukka.rahkonen <at> mmmtike.fi> writes: > >> > >> I took some timings: > >> > >> ogr2ogr -f GPKG germany.gpkg germany.osm.pbf -gt 20000 -progress > >> --config OSM_COMPRESS_NODES YES > >> Timing: 18 minutes > >> > >> ogr2ogr -f GPKG germany_2.gpkg germany.osm.pbf -progress > >> --config OSM_COMPRESS_NODES YES > >> Timing: 2 hours and 11 minutes > > > > Jukka, > > If anyone has > > an objection to raise against 20000 instead of 200, please speak up. > > > > Even > > > >> > >> -Jukka- > >> > > > > Does -gt 65536, which is a high value mentioned in the docs have a > performance penalty for other RDBMS? I use it on Spatialite and > PostgreSQL db's without issues. > > Donovan
I do not believe it is so much about performance but perhaps at some time RDBMS whith is accessed through a slow network would get a timeout and decides to do a rollback. And RDBMS must also reserve resources for being able to rollback the whole transaction. The -gt option is still there and 20000 is hundred times more than 200 so it feels like a good new default. Actually I have been thinking that rollbacks with ogr2ogr are rather useless. If RDBMS rollbacks just one block user must still try again with the whole dataset because there is no way to know which transaction failed and having 999800 rows out of million written into DB is as good as having no rows at all. Thus it could be a good strategy to try to do the whole conversion into database as a one single transaction. Then the rollback would behave in a logically correct way with ogr2ogr "either all or nothing". The cost was discussed already: reserved DB resources for being able to do rollback. But perhaps this is not enough strong argument for having an ogr2ogr option "-gt auto" for single transactions. -Jukka Rahkonen- _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
