Heap Dump
ELI5 - The Vibe Check
A heap dump is a full snapshot of every single object living in your program's memory at one exact moment, frozen so you can poke through it later. When memory keeps climbing and you don't know why, you take a heap dump, load it into a viewer, and start asking wait, why are there twelve million of these objects still alive.
Real Talk
A heap dump is a snapshot of all objects and their reference graph in a program's managed heap at a point in time, used to diagnose memory leaks and excessive memory usage. Analysis tools let you sort objects by retained size and trace reference chains back to find what is unexpectedly holding a reference and preventing garbage collection.
When You'll Hear This
"Take a heap dump in staging before it OOMs in prod." / "The heap dump showed a cache that never evicted anything, that was the leak."
Related Terms
Garbage Collection (GC)
Garbage collection is your programming language's automatic cleanup crew. When you create variables and objects, they take up memory.
Memory Fragmentation
Memory fragmentation is what happens when your program has plenty of free memory in total, but it's scattered around in small, useless chunks instead of on...
Memory Leak
A memory leak is when your program keeps grabbing more memory but never gives it back, like filling a bathtub without a drain.
Profiling
Profiling is watching your program run and keeping score of where the time and memory actually go, instead of guessing.