Add note for changing Heroku's release dyno type

docs/notes/infrastructure/heroku-release-type.md

@@ -0,0 +1,28 @@
+---
+title: Scaling Heroku's release type
+tags:
+  - Heroku
+---
+
+During `release`, it's possible to consume so much memory, Heroku kills the dyno before it finishes executing.
+
+```
+heroku[release.xxxx]: Process running mem=1038M(202.8%)
+heroku[release.xxxx]: Error R15 (Memory quota vastly exceeded)
+heroku[release.xxxx]: Stopping process with SIGKILL
+heroku[release.xxxx]: Process exited with status 137
+heroku[release.xxxx]: State changed from up to complete
+```
+
+When that happens, the release fails (even though it may say "complete"). Whilst it's a good idea not to use huge amounts of memory during release, sometimes it's unavoidable.
+
+Releases run in a `Standard-1X` dyno, regardless of what the other dynos are set to. This has a 512MB RAM limit, however Heroku will let it push over for short periods.
+
+Setting the `release` dyno type can't be done from the dashboard, but can be done from the CLI:
+
+```
+heroku ps:type release=Standard-1X -a <app>
+```
+
+!!! warning
+    When running `Eco` or `Basic` dynos, the release container is configured to match. It's not possible to use other types of dyno on these plans.