> For an unknown reason, Logger died few days ago while writing the history. The
> file mhf_1489577446_20170315_system.dat was created, but was empty.

I ran into same problem installing new midas in the alpha experiment at cern. It should be fixed now:
https://bitbucket.org/tmidas/midas/commits/788021d9cb39a348a40e36f1b35b1440e06aa744

K.O.

> 
> When trying to restart Logger, I would get a seg fault without any special error
> message.
> 
> I tracked the issue to the "read_file_schema" function in history_schema.cxx
> 
> * L4731, a pointer to HsFileSchema *s is declared.
> * L4747, We enter a while(1) loop.
> * L4749, get char on the filename.
> In our case, the file was empty, so the variable "b" gets NULL and the loop breaks.
> 
> Problem: the memory allocation for "s" is later in the loop, L4768.
> Upon exiting the loop, L4854, we try to access record_size on a NULL pointer ==>
> SegFault. 
> 
> It would be nice to at least have a message before breaking the loop...