Could be useful: ability to recover without exception if a database connection is lost abruptly.
RuntimeError: PSQL error: server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. Full sql was: 'SELECT AsBinary("way",'NDR') AS ...
The priority behavior should be to maintain the ability to open new connections to a running postgres database server, but this above edge case would also be good to look into.
As of mapnik-2.2.x with libpq 9.1.12-0ubuntu0.13.10 a backend crash results in PQerrorMessage(conn_) returning an empty string, making the error less informative:
Error: layer0: Postgis Plugin:
Full sql was:...
Dunno if it's a libpq-9.3 issue or a mapnik issue, or something in higher layers...
great thanks for confirming this crash is gone. Now that error message is fixed as of #2173, closing.