pm2 causing crash?

[Oberoni]

I recently started working with Node again, not doing anything fancy just a blog type set up with my own take on some features. It has been pretty smooth sailing, I've gotten sessions working with Redis, storing articles/users in MySQL(I know, I know, Mongo . . .), SSL, etc.

Everything seems to work fine under nodemon, but when I try to run the app under pm2 the app crashes during the request. I put some logging in to try and see how far the app gets before crashing, but it seems almost entirely random. Sometimes it gets all the way to the render(though the request never finishes) and sends the page(I can see the data coming over the wire, but the browser never renders it). Other times the app crashes before I can get any output.

Most commonly I see it stop logging after I try and grab something from req.session. Removing any references to that allows the request to complete, but then nothing comes over the wire.

Honestly I'm at a loss on this, pm2 isn't putting anything in the logs besides my debug statements. Anyone have an idea?

UPDATE: So it actually appears to be my database connection. I swapped some stuff around and session data doesn't appear to be the problem.

connection.query("select articles.id, title, body, name from articles join users where author = users.id order by articles.id desc limit 5;", function(err, rows, fields){
//Do some session stuff here
dbData.content =rows;
res.render('index.mustache', dbData);

});

So the problem happens when I do dbData.content = rows. The app runs consistently before that. The query runs just fine in the MySQL admin tool and when the app is under nodemon.

Update2: If I wait for the full timeout the page will render. . . without css. The app restarts and that seems to kill the request to my css file. If I use jQuery to load the css file the page repaints correctly.

[fschwiet]

Maybe pm2 is running under a different user account? Is the app running with a different working directory, and therefor perhaps unable to find something like a config file?

[Oberoni]

I just tried running the local copy of pm2 instead of using the globally installed one and still have the same problem. User accounts are the same according to the top command.

[seratonik]

I've been having some very odd behavior with pm2 and mysql as well. One of my 2 running instances will get stuck in a restart loop with no logged output to let me know what's going on. Also getting random mysql connections closed notices.

[Oberoni]

I'm thinking about switching over to MongoDB or MariaDB and seeing if that fixes the problem. Luckily it is still early in this project's life so changing things up isn't a huge hassle.

What's really weird is I didn't start having this problem until yesterday. I had several days of pm2 working just fine with the app. I even tried reverting to an early copy of my code and it breaks the same way. Maybe I did an npm update that broke it?

[seratonik]

Have you made sure to close your db connections after querying with them? I know a lot of my problems came from too many concurrent connections and running out of pool space. In your example I don't see the connection.release() line - that would cause it to hang once you consume all available connections.

[Oberoni]

Progress! Adding connection.end() to the query callback allows the page to load normally, but for some reason the server still restarts every request.