Lazy behaviour when parallel requests

[pirhoo]

Hi,

I have a curious behaviour that I still can't explain after 2 days of investigation. When I execute several queries with neo4django at the same time (or very close), the process gets lazy and the request never ends (probably because the previous one is not done).

I got this bug with neo4j 1.8.2 and 1.9.1, and Django 1.4.4 and 1.5.4. I can't give more detail because the only way to provoke this bug is to madly refresh a page.

Thanks for the amazing work,
Pierre

[mhluongo]

Hm, there is some transactional logic related to the in-graph type tree- maybe that's involved? What sort of requests are they, read or write?

[pirhoo]

Mainly read and without any particular conditions: I succeed to reproduce this bug with a simple User.objects.all() (among 20 nodes).

[mhluongo]

Hm, that's no good. Is it using the dev server or in production? If it were reproducible using, say, the requests library and threads, that'd be easier to test & fix.

[pirhoo]

Interesting: it seems that the bug doesn't happen in production (on heroku).

[mhluongo]

Aha! Good, I was worried. It might be because the Django dev server is
threaded, while production is usually process-based. To test that I believe
there's a '--nothreading' (or similarly named) argument to runserver.
Maybe give that a shot? Regardless this sounds like a bug, but we'll see
whether it's a big or little one.
On Oct 25, 2013 5:56 PM, "Pierre Romera" [email protected] wrote:

Interesting: it seems that the bug doesn't happen in production (on
heroku).

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[pirhoo]

OK, that sounds reassuring. I'm trying what you propose.

[tonjo]

Hmm, and threading would worsen performance?
Il 26/ott/2013 00:07 "Pierre Romera" [email protected] ha scritto:

OK, that sounds reassuring. I'm trying what you propose.

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[pirhoo]

Ha! Good news: the --nothreading option fix it, thanks!

I don't think we can consider this issue as solved so I let you decide if we should close it.

[mhluongo]

No, I'll leave it open. It's going to be fun to debug :)
On Oct 25, 2013 6:19 PM, "Pierre Romera" [email protected] wrote:

Ha! Good news: the --nothreadinghttps://docs.djangoproject.com/en/dev/ref/django-admin/#django-admin-option---nothreadingoption fix it, thanks!

I don't think we can consider this issue as solved so I let you decide if
we should close it.

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[pirhoo]

OK, you're the boss. Thanks again, you saved my weekend!