Software Applications

Darktable Crashing

Darktable is a robust, full-featured, open source digital darkroom. Despite all of its great qualities, whenever I was trying to export images (all editing is non-destructive), Darktable crashed; sometimes after 25 images, sometimes during a single image export. 

A few notes about the system that I was using:

  • Windows 10.0.17134
  • AMD A8-6500 CPU
  • AMD Radeon HD 8570D GPU

The error message is displayed in the image on the right. Multiple attempts to export images were made after: Windows updates; video card driver updates, uninstall-reinstall Darktable, etc. All of the error logs had a common feature: amdoc164.dll. 

Export worked! - after disabling the AMD Radeon video card. When exporting was complete, I enabled the video card again and life is good.


Darktable error message: An unhandled exception occured. Backtrace will be written to: C:UsersuserAppDataLocalTempdarktable_bt_TRAWPZ.text after you click on the OK button. If you report this issue, please share this backtrace with the developers.

Sidebar to the Darktable crashing problem:

I also have Darktable running on Ubuntu 18.04. After banging my head against the wall for a couple of hours, trying to get the photos to export on my Windows machine, I plugged my external hard-drive with the RAW files and Darktable sidecar files into my Ubuntu laptop. It would seem that the header information in the .xmp files was compatible between Windows and Ubuntu, because the image tags written to the sidecar file were preserved. But all of the exposure, contrast, colour, etc. information was not being applied. 

I realize that there is just something simple in the syntax of the .xmp file that needs to be changed but after another hour or two of banging my head against the wall I was unable to fix the problem. I had already spent many hours editing hundreds of photos and so redoing the image corrections or the need to batch edit hundreds of sidecar files (assuming that I would solve the .xmp formatting problem) was daunting.

I hope to clear up this problem of transferring the sidecar files between Windows and Linux systems in the future. Until then, it is my Windows box that has the nice-size dual monitors and so I will continue to edit there instead of moving the editing to the less buggy linux distro.

All of my complaints and exporting headaches aside: Darktable is awesome!

Forgot Postgreql Password

I have hundreds of usernames and passwords and I'm usually pretty conscientious about adding them to my password manager. After installing Postgresql on a new workstation, I was in a hurry to query some Canada Census data. (Dissemination Area level data is usually too big to open in Excel or Access and Postgresql is my go-to database for Census data.) I probably wrote the password down on a scrap of paper and never entered it. 

My first step to resetting the password followed the instructions on StackExchange here: except that instead of inserting the recommended line or modifying an existing line, I changed the Method in all 4 lines in the pg_hba.conf file from "md5" to "trust". The original file is shown below on the left and my edits are in the image below on the right.

The above worked and I was able to log into postgresql using the psql terminal without being asked for a password. I then followed the second upvoted StackExchange answer at: to reset the password. Using the command:

password postgresql

I was prompted to enter a new password. After quitting postgresql, I then changed the name of the altered pg_hba.conf file to "pb_hba.conf_altered_password_reset" and then using the original pb_hba.conf file I was able to log into postgresql with the new password.