Randomly occurring PostGIS errors

[freder]

I just set up a tile server, using tilelive-mapnik with tessera, which works just fine in the browser. however, with the script I'm using to scrape tiles and save them to file, I sometimes get these errors:

GET /12/2204/1346@2x.png 500 2220.111 ms - 311
Error: PostGIS: geometry name lookup failed for table ''. Please manually provide the 'geometry_field' parameter or add an entry in the geometry_columns for ''.

GET /12/2204/1346@2x.png 500 632.895 ms - 165
Error: Postgis Plugin: Null connection

feels very random.

essentially I'm just making http requests to the server, so I'm not even sure what the problem might be (and why it doesn't seem to happen in the browser).

→ the script

[freder]

update: I just noticed that it also happens in tileoven (when I'm zooming in very quickly?)

[zdila]

check max_size mapnik config parameter if it is big enough