Timeout errors when making lots of calls

[pdilyard]

When many requests are made (in my case, synchronously), I eventually get the following error message:

** (exit) exited in: :gen_server.call(#PID<0.644.0>, {:operation, :command, [{:raw, "s"}, 194, {:raw, <<0, 0, 0, 1, 99>>}, {:raw, [<<0, 0, 0, 159, 67, 82, 69, 65, 84, 69, 32, 69, 68, 71, 69, 32, 104, 97, 115, 95, 100, 101, 109, 111, 103, 114, 97, 112, 104, 105, 99, 95, 114, 101, 115, 112, 111, 110, 115, 101, 10, 70, 82, ...>>, <<1>>, [<<0, 0, 0, 20>>, [0, [[<<0>>, ""], [[[[<<20>>, "parameters"], <<0, 0, 0, 19>>, 12]], 0, [[<<0>>, [], []]]]]]], <<0>>]}]}, 5000)
    ** (EXIT) time out
        (stdlib) gen_server.erl:212: :gen_server.call/3
    (marco_polo) lib/marco_polo.ex:831: MarcoPolo.refetching_schema/2
     (ex_orient) lib/ex_orient/db.ex:29: anonymous fn/3 in ExOrient.DB.command/2
       (poolboy) src/poolboy.erl:76: :poolboy.transaction/3
      (hydrogen) lib/migrator/agents_agentattribute.ex:12: anonymous fn/1 in Migrator.AgentsAgentAttribute.run/1
        (elixir) lib/enum.ex:610: anonymous fn/3 in Enum.each/2
        (elixir) lib/enum.ex:1478: anonymous fn/3 in Enum.reduce/3
        (elixir) lib/stream.ex:1227: anonymous fn/3 in Enumerable.Stream.reduce/3
        (elixir) lib/enum.ex:2744: Enumerable.List.reduce/3
        (elixir) lib/stream.ex:732: Stream.do_list_transform/9
        (elixir) lib/stream.ex:1247: Enumerable.Stream.do_each/4
        (elixir) lib/enum.ex:1477: Enum.reduce/3
        (elixir) lib/enum.ex:609: Enum.each/2
      (hydrogen) lib/migrator/all.ex:69: Migrator.All.migrate/1

[whatyouhide]

Hey there, do you have a minimal way of reproducing this?

[pdilyard]

I've been able to replicate it most easily by inserting a lot of records, say 50,000, and then running a query to select them all. Even if you set your timeout to 60_000, the refetching_schema call will timeout in 5 seconds.

Not sure if this matters or not.

Also keep in mind that this isn't something I would typically do, it's actually for a huge, one-time batch operation.

[whatyouhide]

I see, very interesting! Could you setup a small repo that I can use to reproduce this easily? I understand the process (it looks really straightforward) but I won't have time to look into it until the weekend, and a way to reproduce this right away would definitely be of help :)

[pdilyard]

I can't seem to reproduce this consistently. It only seems to happen after I insert a lot of data into Orient. I've tried restarting the app, restarting Orient, etc. I can make queries like normal in the OrientDB interface, but I cannot make them through MarcoPolo, as the refetching_schema function repeatedly times out.

I'm trying to migrate data to Orient, and I can't seem to get a reliable result.

[whatyouhide]

So every time you make 50k INSERT queries and then a query to select all the inserted records you get this timeout?

[pdilyard]

I've found that it's actually more of a random number of inserts, but basically, yes. I'm looking through the marco polo source and don't really see why it even needs to fetch the schema of the database at all - is there a way I could just disable this temporarily?

[whatyouhide]

@pdilyard that's how OrientDB works, the binary protocol isn't self-contained and for schemaful records it returns the type of their properties as "type ids" to be looked up in the database schema. 😕 It's not a great design to work with IMO, but it's what we have right now ¯_(ツ)_/¯

[pdilyard]

Hmm. Well this is a huge blocker for me right now, I can't successfully get a migration script to work all the way through without this function timing out. Is there anything at all I can do about it?

[whatyouhide]

Sorry to hear, but I will not be able to work on this very soon. I may be able to give it a shot this week but cannot guarantee. What you can do is try and debug this, maybe find the bug and even better, a fix, and submit a PR :) That's open source at its finest! :P

On Sunday, 14 August 2016, Paul Dilyard [email protected] wrote:

Hmm. Well this is a huge blocker for me right now, I can't successfully get a migration script to work all the way through without this function timing out. Is there anything at all I can do about it?

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Andrea Leopardi [email protected]