A little while ago I already described this issue in the Elixir IRC channel. It went away after I switched from MySQL to MariaDB but now I’m encountering it again on a server where I’m deploying my code and have no say in the exact version of MariaDB/MySQL being employed.
The heart of the issue is that, presumably with certain versions of MariaDB/MySQL, Repo.get/2 doesn’t work with binary keys.
Here is how I would normally try to retrieve a DB record:
uuid = "44337bf3-51c2-41d5-b7ac-31eabd5c43da"
MyApp.Repo.get(MyApp.User, uuid)
This works just fine on my local test machine.
On the server, however, I get this:
uuid = "44337bf3-51c2-41d5-b7ac-31eabd5c43da"
NowDoApi.Repo.get(NowDoApi.User, uuid)
#19:53:50.236 [debug] QUERY OK source="users" db=2.0ms
#SELECT u0.`uuid` […] FROM `users` AS u0 WHERE (u0.`uuid` = ?) [<<68, 51, 123, 243, 81, 194, 65, 213, 183, 172, 49, 234, 189, 92, 67, 218>>]
#=> nil
The database connection is established just fine and the UUID is also correct as evident by the following test:
user = MyApp.Repo.all(MyApp.User) |> Enum.find(fn user -> user.uuid == uuid end)
#=> %MyApp.User{[…], uuid: "44337bf3-51c2-41d5-b7ac-31eabd5c43da"}
To make sure there wasn’t any encoding problem with my string, let’s try again with the uuid that was retrieved by the previous query:
MyApp.User |> where(uuid: ^uuid) |> MyApp.Repo.all()
#19:57:20.551 [debug] QUERY OK source="users" db=2.0ms
#SELECT u0.`uuid`, […] FROM `users` AS u0 WHERE (u0.`uuid` = ?) [<<68, 51, 123, 243, 81, 194, 65, 213, 183, 172, 49, 234, 189, 92, 67, 218>>]
#=> []
This I find rather astonishing.
Has anyone here encountered a similar problem or found a way around this?
I am using Elixir 1.4.0 with Mariaex 0.8.0 and Ecto from Git master. The DB server is MariaDB 5.5.42.
Edit: I just upgraded to Mariaex 0.8.1 and switched to Ecto 2.1.3, but that makes no difference.
Edit 2: A similar problem was reported by someone in the Ecto mailing list half a year ago but no solution was posted there either.
