Always catch StandardError in Threads and release connection

app/helpers/action_cable_helper.rb

@@ -13,6 +13,8 @@ module ActionCableHelper
             locals: {request_for_comment: self})
         )
       end
+    rescue StandardError => e
+      Sentry.capture_exception(e)
     ensure
       ActiveRecord::Base.connection_pool.release_connection
     end
@@ -33,6 +35,8 @@ module ActionCableHelper
           working_time_data: exercise.get_working_times_for_study_group(study_group_id, user)
         )
       end
+    rescue StandardError => e
+      Sentry.capture_exception(e)
     ensure
       ActiveRecord::Base.connection_pool.release_connection
     end

app/models/submission.rb

@@ -312,6 +312,8 @@ class Submission < ApplicationRecord
           rfc.full_score_reached = true
           rfc.save
         end
+      rescue StandardError => e
+        Sentry.capture_exception(e)
       ensure
         ActiveRecord::Base.connection_pool.release_connection
       end

lib/prometheus/controller.rb

@@ -19,6 +19,8 @@ module Prometheus
             initialize_rfc_metrics
           rescue StandardError => e
             Sentry.capture_exception(e)
+          ensure
+            ActiveRecord::Base.connection_pool.release_connection
           end
         end
       end

lib/runner/event_loop.rb

@@ -32,6 +32,8 @@ class Runner::EventLoop
       queue = Queue.new
       Thread.new do
         EventMachine.run { queue.push nil }
+      rescue StandardError => e
+        Sentry.capture_exception(e)
       ensure
         ActiveRecord::Base.connection_pool.release_connection
       end