4 ms·

> Java has a big selection of GCs, and each has their bunch of knobs for tuning. And you have to pay attention to that stuff. You never have to touch them in t

> Java has a big selection of GCs, and each has their bunch of knobs for tuning. And you have to pay attention to that stuff. You never have to touch them in the Java world either, unless you like making performance worse that is. I've never ever seen a case where fiddling with garbage collection parameters didn't make things slower. I worked with a guy who worked on a popular java compiler, and he says the same thing. he never twiddles GC parameters either.

nemothekid 7y ago
Cassandra has benefitted from so many GC tweaks that I find this view hard to believe. i can only imagine someone having this view if they have never cared about latency. How have you never experienced a multi-second GC pause on default CMS settings?
tomohawk 7y ago
What sort of scale are you working at? At our scale, it is normal to look into these sorts of things. Reading and understanding and applying articles like the following is absolutely necessary. http://clojure-goes-fast.com/blog/shenandoah-in-production/ http://clojure-goes-fast.com/blog/shenandoah-in-production/
- gerbilly 7y ago
  Medium scale. It's not like I need to pimp each of my servers like it's a Honda Civic. If the load gets too high, I just add another instance. It's way more economical than wasting developer time fiddling with GC params.
imtringued 7y ago
Are you serious? You have to mess with the maximum memory allocated to the GC all the time with java processes. Also the JVMs default settings basically assume it is the only process running. It will keep hogging a huge amount of memory even if the memory allocated to the GC is 60% empty unless you configure the GC properly. Wasting memory and stealing it from other processes which potentially causes swapping or crashing is far worse than any increased time spent garbage collecting. Unless you're as stupid as the Minecraft developers you will rarely suffer from GC pressure with heaps below 10GB.

nemothekid 7y ago

Cassandra has benefitted from so many GC tweaks that I find this view hard to believe. i can only imagine someone having this view if they have never cared about latency. How have you never experienced a multi-second GC pause on default CMS settings?

tomohawk 7y ago

What sort of scale are you working at? At our scale, it is normal to look into these sorts of things. Reading and understanding and applying articles like the following is absolutely necessary. http://clojure-goes-fast.com/blog/shenandoah-in-production/ http://clojure-goes-fast.com/blog/shenandoah-in-production/

gerbilly 7y ago
Medium scale. It's not like I need to pimp each of my servers like it's a Honda Civic. If the load gets too high, I just add another instance. It's way more economical than wasting developer time fiddling with GC params.

imtringued 7y ago

Are you serious? You have to mess with the maximum memory allocated to the GC all the time with java processes. Also the JVMs default settings basically assume it is the only process running. It will keep hogging a huge amount of memory even if the memory allocated to the GC is 60% empty unless you configure the GC properly. Wasting memory and stealing it from other processes which potentially causes swapping or crashing is far worse than any increased time spent garbage collecting. Unless you're as stupid as the Minecraft developers you will rarely suffer from GC pressure with heaps below 10GB.