highload2019

Status

Aborted competition - docker container didn't make it through OOM, even with stable 300 MB free RAM left.

Stats:

• Time spent : 100+ hours
• Kotlin gotchas found : 15+
• Critical Kotlin gotchas found (nearly switched back to Java) : 3+
• Learned new JVM flags : 50+
• Custom iterators written : 7
• Stable JVM crashes(passing Java Integer to Kotlin Int) : 1

Achievements:

• 6.5k GET RPS on 8 cores
• Handmade indexes, with possible merging. (Partitioned arrays of int arrays with ids sorted by descending)
• Learned a lot about memory model, optimizations and profiling
• Total used memory after loading all data in RAM with indexes: 1201 MB

Doubtful achievements

• Tried procedural programming
• Tried off-heap collections
• Leaned more about bit operations
• Manual to byte JSON serialization
• Manual byte handling
• Tried Epoll(0)
• Tried java 11
• Tried gradle kotlin dsl

• Will ever use 'ranges': no