1/30/2024 0 Comments Death Trash for ios download free![]() ![]() The question I asked myself was “what in the application caused this excessive GC?”. Also notice how the heap (red line) has because exhausted and that CPU spiked when GC kicked in as expected. You can see in the screenshot below the sudden leap in GC time (top green line) from around 5 seconds per minute to well over 100 seconds per minute. ![]() Next I drilled down into this JVM and plotted its GC time, % CPU Busy and % Heap utilization before, during and after the reported slowdown at 7pm. You can see from the screenshot below that one JVM had 17 major collections with most other JVMs just having a single collection: This is where I noticed one JVM was spending a significant amount of time in GC, an average of 23 seconds per minute compared, to the others which were averaging 2-3 seconds. So I then looked at JVM metrics to check CPU, memory (heap) and garbage collection activity. The first place I checked was the system OS metrics, specifically looking for high CPU, memory, disk I/O and network I/O – the classic KPIs a typical sys admin might check. Here is the application topology (system map) showing the traffic and performance spike: It has 20+ JVMs, 2 relational databases, an MQ messaging backbone and several 3rd party web services. This application processes on average around 25 million business transactions a day, which is roughly 18,000 transactions a minute. The customer reported an application slowdown around 7pm in the evening. Here is what I found while troubleshooting. I was troubleshooting a performance issue with a customer’s application last week and witnessed significant GC times of around 90 seconds. The problem is when GC takes more than a few seconds, especially now that JVM memory and heaps can be as large as 16GB – collecting MBs can take seconds, but GBs can take minutes. It’s not such a big deal when GC runs for a few seconds, say, every minute, as this is typical for an active application that persists data frequently from databases (disk) to JVM (memory). When the GC thread in the JVM kicks in all other threads grind to a halt, giving the end user an impression that the application is slow. Java memory becomes filled with redundant objects/data which over time must be collected so that memory can be reclaimed and reused by the JVM. Every man and his dog knows that Garbage Collection (GC) is a “stop the world” event. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |