Reporter: tbabut[at]mobileobjects.de
[Submitted to the original trac issue database at 9.56pm, Tuesday, 17th May 2011]

Hello,

with recent mod_tile version and mapnik2 the renderd is crashing sporadically on concurrent requests with the following messages:

renderd[4751]: DEBUG: Got command RenderBulk fd(22) xml(default), z(9), x(32), y(176)
renderd[4751]: DEBUG: Got command RenderBulk fd(20) xml(default), z(9), x(32), y(184)
renderd[4751]: DEBUG: Got command RenderBulk fd(21) xml(default), z(9), x(32), y(192)
renderd[4751]: DEBUG: Got command RenderBulk fd(16) xml(default), z(9), x(32), y(200)
renderd[4751]: DEBUG: Got command RenderBulk fd(17) xml(default), z(9), x(32), y(208)
/var/lib/mod_tile/default/9/0/0/0/37: File exists
renderd[4751]: Received error when writing metatile to disk, requesting exit.
terminate called after throwing an instance of 'std::runtime_error'
what(): dead reference!

The render daemon runs on Debian Squeeze 6.0 and the filesystem is XFS.

Please take a look at the following thread, too:
http://forum.openstreetmap.org/viewtopic.php?id=12306

We have created a patch (attached to this ticket), that seems to resolve the problem.

Thanks in advance.

Kind Regards,
Thomas Babut