It's still a huge whoosh. You're starting at 1.9 and you're testing 4 micro versions to 1.10.. what is the point of that? None of those non-major versions are going to significantly change how the GC works.
They could have tried 1 other version (not 4) and picked either the latest (1.13) or the version that contains the GC improvements (1.12) to test. Usually when you are looking to upgrade something you skim the release notes so testing 1.12 or 1.13 is obvious especially when 1.12 seems to specifically address their performance concern.
If upgrading something avoids a service re-write that is usually the way to go unless you were looking for an excuse to re-write the service in the first place which may have been the case.
edit:
It turns out they did exactly what my comment stated: they tested the latest version (1.10). It's just that this article was published recently but the events happened quite a while back.
Except that you literally said it wasn't surprising b/c gc sucks. You were "not surprised" in response to the assumption that they DIDN'T test the latest version. However this was just a mis-understanding and you're re-casting your comment to make it seem like you were right all along. If you knew they tested the latest version all along then you couldn't have been surprised or not surprised to something that didn't happen.
It seems like my comment was just an entry point for you to shit on gc which, ironically, I mostly agree with in this context.
According to another comment they did this back in May 2019 when 1.10 was the latest. They are only blogging about it now which I guess is slightly unfortunate but never the less.
They could have tried 1 other version (not 4) and picked either the latest (1.13) or the version that contains the GC improvements (1.12) to test. Usually when you are looking to upgrade something you skim the release notes so testing 1.12 or 1.13 is obvious especially when 1.12 seems to specifically address their performance concern.
If upgrading something avoids a service re-write that is usually the way to go unless you were looking for an excuse to re-write the service in the first place which may have been the case.
edit:
It turns out they did exactly what my comment stated: they tested the latest version (1.10). It's just that this article was published recently but the events happened quite a while back.