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Repo.stream + Flow.from_enumerable

#ecto#streams#flow
apr

apr

Repo.stream + Flow.from_enumerable

I have the following code

Repo.transaction(fn -> Blog |> where(title: ^title) |> Repo.stream() |> Flow.from_enumerable() |> Flow.each(fn x -> IO.inspect x end) |> Flow.run() end)

When I run this, I get the error: (RuntimeError) cannot reduce stream outside of transaction

Is Ecto and Flow not supposed to be used in this manner?

Thanks!

6 comments
#ecto#streams#flow
13 3985 6

Marked As Solved

mbuhot

mbuhot

I believe the stream must be used in the same process that created the transaction.

There was some work towards GenStage integration in Ecto: https://github.com/elixir-ecto/ecto/pull/2028 but it’s been closed.

1
Post #2

Also Liked

josevalim

josevalim

Creator of Elixir

We will support this likely on Ecto 3.1. It won’t make the cut for Ecto 3.0 but it is planned to happen at some point.

6
Post #4
josevalim

josevalim

Creator of Elixir

It has not. Unless someone works on it (or sponsors someone do to the work), it is unlikely to be added.

3
Post #7
samuelralak

samuelralak

Has it made the cut yet?

1
Post #5

Where Next?

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