Performance drop after 5 days running web application, how to spot the bottleneck?

Question

I've developed a web application using the following tech stack:

• Java
• Mysql
• Scala
• Play Framework
• DavMail integration (for calender and exchange server)
• Javamail
• Akka actors

On the first days, the application runs smoothly and without lags. But after 5 days or so, the application gets really slow! And now I have no clue how to profile this, since I have huge dependencies and it's hard to reproduce this kind of thing. I have looked into the memory and it seems that everything its okay.

Any pointers on the matter?

Answer 1

Try using VisualVM - you can monitor gc behaviour, memory usage, heap, threads, cpu usage etc. You can use it to connect to a remote VM.

Answer 2

`visualvm˙ is also a great tool for such purposes, you can connect to a remote JVM as well and see what's inside.

I suggest you doing this:

• take a snapshot of the application running since few hours and since 5 days
• compare thread counts
• compare object counts, search for increasing numbers
• see if your program spends more time in particular methods on the 5th day than on the 1str one
• check for disk space, maybe you are running out of it

Answer 3

jconsole comes with the JDK and is an easy tool to spot bottlenecks. Connect it to your server, look into memory usage, GC times, take a look at how many threads are alive because it could be that the server creates many threads and they never exit.