"Transaction is not started" solved by changing log level on the Repo.insert

[lessless]

Elixir version

1.18.4

Database and Version

PostgreSQL 17.9 (GCP)

Ecto Versions

3.14.1

Database Adapter and Versions (postgrex, myxql, etc)

0.19.3

Current behavior

A Repo.insert() failed with ** (DBConnection.TransactionError) transaction is not started

Just one in the whole database.

I changed it to Repo.insert(log: :error), pasted the module in the remote shell, and it worked.
I then changed the statement back to how it was, pasted the module again, and it continued to work.

That was consistent across two nodes.

Expected behavior

Repo.insert() doesn't fail with ** (DBConnection.TransactionError) transaction is not started or gives a useful debugging information.

[josevalim]

Please provide a way to reproduce this issue, such as a code snippet, as I am not exactly sure what is going on from the report and it will help us verify the fix. Thank you!

[lessless]

I’m afraid I can’t do that. It was the first time I saw that issue and it was a production incident so we did about as much debugging as we could at the time. The primary goals was getting system back in to the stable system.

In the essence there was just that one insert that failed. Nothing else.

I never saw error like that before.

The same query from the psql on the same machine worked just fine.

What information should I look for next time that happens?

[josevalim]

I need more information. At least a stacktrace. It is very hard for me to give any suggestion when all I have available is the exception name and message.

[lessless]

It was caused by the mode: :savepoint passed to the Repo.insert(). We are looking further into that.

[josevalim]

If you call Repo.insert with mode: :savepoint outside of transaction, then it will indeed fail with that exact reason above:

iex(1)> TS.Repo.insert!(%TS.Accounts.User{email: "test@example.com", name: "Test User",
          external_id: "test-#{System.unique_integer([:positive])}", provider: :github}, mode: :savepoint)
** (DBConnection.TransactionError) transaction is not started
    (ecto_sql 3.14.0) lib/ecto/adapters/sql.ex:1121: Ecto.Adapters.SQL.raise_sql_call_error/1
    (ecto 3.14.1) lib/ecto/repo/schema.ex:1060: Ecto.Repo.Schema.apply/4
    (ecto 3.14.1) lib/ecto/repo/schema.ex:505: anonymous fn/16 in Ecto.Repo.Schema.do_insert/4
    (ecto 3.14.1) lib/ecto/repo/schema.ex:383: Ecto.Repo.Schema.insert!/4
    iex:1: (file)

Which is understandable given that you asked to use savepoints outside of transaction. Are there some code paths where the code is invoked outside of transaction? Do you have the full stacktrace?