Drupal Core's Migrate API maintains an internal table mapping unique source ids to destination ids. This is usually done via a database table that holds the field values that together uniquely identify a source row and the matching destination id of the entity in Drupal.
Looking at a Recent log messages report of one of our Drupal 8 instaces, I came across this error message:
If you need to support obscure URI schemes in your Drupal 8 instance and you're getting error messages about invalid URI schemes, this post is for you.
Suppose you have a view and want to dynamically alter the number of results shown by the view based on the view arguments.
Sometimes you get the error
Out of resources when opening file './database/table.MYD' (Errcode: 24 - Too many open files)
To fix this on Ubuntu 16.04 you have to change the limits and to change the systemd-config: