Again: Web App crashes: Unexpected error 9 on netlink descriptor 9

Targets Web
1

Xojo 2024 4.2: with no changes in my code UrlConnection again raises the netlink errors on Debian 12. This does not happen all the time, after a dozen of fast click with my mouse, causing a bit of a load on UrlConnection, the App crashes.

My App build with Xojo 2024 4.1 remains stable, whatever I do to stress UrlConnection. Also the listboxes in this build seem far less jumpy/nervous while loading data from the ContentReceived event.

Again, this is not reproduceable on Windows or Mac. I am getting a headache about this.
My server config did not change, using still the same Lightsail Debian 12 with 2 processors running only this app. Reverting to the previous version of Xojo solves my problems. However, that is not the way to go.

2

Just for the record, I am seeing the same thing on Ubuntu 22.04 with my web app compiled with Xojo 2024.r4.2, every now and then. It happens when a user saves a record to my PostgreSQL Db, which in turn issues a notification (via pg_notify in a trigger) which again I detect in my databaseConnection object in my web app. I do that to update the data in all connected clients sessions. So no URLConnection involved here. I am not using Lifeboat currently.

3

Hi Maximilian, could there be a outgoing (HTTP) socket being involved for your data update or notifcation to your connected clients?

4

Nope. I basically just update the listboxes showing the updated data.

5

Ha, I just notice the opposite is true - I do make an API call to Twilio to send an SMS in that very moment. The Web app crashes before the socket receives the pageReceived event. So you were spot on - there is an issue making http requests. Good catch!

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6

Is there a way we can have a sample project demonstrating the issue?

I’m wondering if this is happening just with Web projects or are Desktop/Console projects affected as well.

7

Nice! Or not so nice off course. What I have done previously in 2024 4.0 and 4.1 is implement a very short 250 milliseconds Thread.Sleep just before UrlConnection.Send, for some reason that solved my issue in that version.

@Ricardo_Cruz I can share my project privately with Xojo. I have tried to make a sample project for this issue I but did not succeed reproducing the crash. What also is necessary that I share some data with you to connect to a demo Microsoft server and help set it up.

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8

I am afraid no, not by me currently, too busy.
I was using the deprecated Xojo.Net.HTTPSocket, I am just in the process of changing it to URLConnection, but as Jacco is seeing the same thing with URLConnections this probably won’t change things. It also only happens on each 10th or 20th iteration which is for me like once in every 2 days or so.

9

Could you try my suggestion to add a small delay before UrlConnection.Send. What you are seeing is exactly what I was seeing also, every 18 or 20 times a crash.

10

Sure, I can give that a shot. Will know around Friday if it helped. Thanks for the suggestion.

11

No crashes so far. It may have helped indeed. Thanks!

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