Underpass command line utility

underpass is a command line utility for updating databases from changesets and change files, and runs as a system daemon. Both change files and changesets need to be applied to the database to stay in sync. Change data can be downloaded from planet.openstreetmap.org every minute, and has to be applied to the databases. Data is processed as a stream, so a large disk for temporary files or much memory isn’t needed.

The primary mode is to monitor the upstream change data for new files, and to apply them. If the timestamp specifed is in the past, the change data files are downloaded continuously until caught up with the current time.

Each data source uses a different thread for multi-core support and better performance. As files are downloaded from the different sources, they are analyzed, and applied to the appropriate database. Most of the work is done by the Underpass library. underpass is the utility program that a uses the library.

underpass -h
-h [ --help ]         display help
-s [ --server arg]    database server (defaults to localhost)
-m [ --monitor]       Start monitoring planet
-t [ --timestamp arg] Starting timestamp
-i [ --import ] arg   Initialize pgsnapshot database with datafile

By default, underpass uses the last date entered into the OSM Stats datavase as the starting point. A different timestamp can also be specified using --timestamp. All data files downloaded can optionally be cached to disk, so furthur processing can use those and save on network time.