Aggregation Timeout

[Lazarus404]

Hi guys,

I'm getting an error when performing an aggregation on a lot of data

    ** (exit) an exception was raised:
        ** (Mongo.Error) tcp recv: unknown POSIX error - :timeout
            (mongodb) lib/mongo/cursor.ex:154: anonymous fn/5 in 
    Enumerable.Mongo.AggregationCursor.start_fun/5
            (elixir) lib/stream.ex:1392: anonymous fn/5 in Stream.resource/3
            (elixir) lib/enum.ex:2507: Enum.take/2

I've tried passing cursor_timeout: false, timeout: 30_000, pool_timeout: 30_000 to the aggregate options, but nothing fixes it. The documentation doesn't state what and where timeout values should be used.

[Lazarus404]

Anyone? Is there any documentation for this at all? Any suggestions?

[ankhers]

Hey,

Unfortunately I have never been able to track this down. I have not personally seen it in my production system, nor have I been able to reliably reproduce any of these timeout issues. If you can give me information about what was happening within your system and possibly if you could find a way to reliably reproduce the issue, it could help in fixing it.

[Orange-Men]

@ankhers
I have the same issue but I can't understand the pattern when exactly it is thrown and in what circumstances. I guess here plays a role of the amount of data and time of processing (your captain obvious).
I mean that a few identical actions can throw this error or not.

Erlang/OTP 22 [erts-10.4]
Elixir 1.8.2
mongodb 0.4.9
mongodb_ecto 0.2.1
poolboy 1.5.2

{:ok, pid} = Mongo.start_link(database: Application.get_env(:myapp, Repo)[:database])
cursor = Mongo.aggregate(pid, "options", pipeline, [allow_disk_use: true])
prices = Enum.to_list(cursor)

[error] Task #PID<0.11817.0> started from #PID<0.11741.0> terminating
** (Mongo.Error) tcp recv: unknown POSIX error - :timeout
    (mongodb) lib/mongo/cursor.ex:154: anonymous fn/5 in Enumerable.Mongo.AggregationCursor.start_fun/5
    (elixir) lib/stream.ex:1377: anonymous fn/5 in Stream.resource/3
    (elixir) lib/enum.ex:3015: Enum.reverse/1
    (elixir) lib/enum.ex:2647: Enum.to_list/1
    (myapp) web/models/action.ex:553: MyApp.Action.get/3
    (elixir) lib/task/supervised.ex:90: Task.Supervised.invoke_mfa/2
    (elixir) lib/task/supervised.ex:35: Task.Supervised.reply/5
    (stdlib) proc_lib.erl:249: :proc_lib.init_p_do_apply/3