Hello everyone,
after experiencing database stability issues with postgis since the end of July, which made using the OpenStreetMap database more or less impossible, we have finally managed to identify the issues and have hopefully found a stable workaround.
After a full re-import of the data, the OpenStreetMap database on Ptolemy is now back up-to-date. In most cases replication delay to the main OpenStreetMap database is 5 minutes, but during busy times typically afternoon to evening European time, the replication delay can be larger as the server can't always keep up with replication.
With the Database, the services using it, should also be mostly up-to-date again. This includes WIWOSM, client side rendering in WikiMiniAtlas and the the tiles in various styles provided by the toolserver used in e.g. the osm-gadget in a number of Wikipedias. (The tile rendering is actually still catching up with the backlog of changes for a while).
Any other services using the database should also be up-to-date again, and everyone who has a toolserver account should, as previous, be able to read-access the database via "psql -h sql-mapnik -d osm_mapnik" from any of the toolserver login servers if they want to experiment with the OpenStreetMap data.
The initial issue with the crashing database turned out to be a problem with PostGIS. The function ST_Intersection crashes postgresql if it operates on invalid polygons (e.g. self intersecting polygons). As the OpenStreetMap data model is very flexible and lenient, nothing stops people from entering invalid polygons and the import tools currently don't filter these out. So the database contains quite a few invalid polygons that can cause issues with PostGIS.
In future we might fix the import tools to exclude invalid polygons to begin with, but for now everyone who uses the database will need to use the following workaround: When ever you use a query on the planet_polygon table, you should add a "where ST_IsValid(way)" condition to the query to ensure it only processes valid geometries.
If anyone still experiences any issues, please let me know.
Kai