Add rake task `db:obsolete_ignored_columns`

Show a list of obsolete `ignored_columns`

1 files changed, 21 insertions, 0 deletions

diff --git a/lib/tasks/db_obsolete_ignored_columns.rake b/lib/tasks/db_obsolete_ignored_columns.rake
new file mode 100644
index 00000000000..184e407f28c
--- /dev/null
+++ b/lib/tasks/db_obsolete_ignored_columns.rake
@@ -0,0 +1,21 @@
+desc 'Show a list of obsolete `ignored_columns`'
+task 'db:obsolete_ignored_columns' => :environment do
+  list = Gitlab::Database::ObsoleteIgnoredColumns.new.execute
+
+  if list.empty?
+    puts 'No obsolete `ignored_columns` found.'
+  else
+    puts 'The following `ignored_columns` are obsolete and can be removed:'
+
+    list.each do |name, ignored_columns|
+      puts "- #{name}: #{ignored_columns.join(', ')}"
+    end
+
+    puts <<~TEXT
+
+      WARNING: Removing columns is tricky because running GitLab processes may still be using the columns.
+
+      See also https://docs.gitlab.com/ee/development/what_requires_downtime.html#dropping-columns
+    TEXT
+  end
+end