# Fast, Distributed and Persistent: A new Model for key value stores --- - Why is it important? :exclamation: - Zebra :zebra_face: - Goal :bow_and_arrow: - Approaches & Evaluation :motorway: - Tenacious Zebra :confetti_ball: --- # Why is it important? :exclamation: --- Key value storage are used everywhere - Gaming - Session managment (Redis) - Blockchain Technologies - etc. --- Recent improvements for consesus: - BFT-SMART [2014] - HotStuff [2019] - Chop Chop [2023] --- ## What are the new bottlenecks? - performance on the nodes themself --- # Zebra :zebra_face: --- - Uses a Merkle Patricia trie - Uses multiprocessing on subtries - Hashmap for each thread <img src="https://hackmd.io/_uploads/BJo5rBwoT.png" width="400px" /> --- - Cheap snapshot (O(1)) - Integrity detection - Efficient sending - Efficient storing --- ## No Persistency! --- # Goal :bow_and_arrow: --- Find a solutions for zebra that satisfies following criterias: - Modifications should be persistently saved - Atomicity - Performance should be "reasonable" well --- # Approaches :motorway: --- ## Store database ## vs ## Store changes (WAL) --- - **No backup:** Baseline - **No backup dashmap:** Concurrent hashmap alternative - **File Backup:** Simple solution - **Multiple PickleDB:** One DB for each thread - **Okay WAL:** Use an existing WAL implementation - **RocksDB WAL:** Use RocksDB as a WAL --- ## Testing --- Anazlyzing: - Machine with 96 Cors - Write Percentage - Transaction size --- ### Write percentage 100 Transaction with 100'000 operations <img heihgt="500px" width="600px" src="https://hackmd.io/_uploads/BJfww-Lop.png" /> --- ## 10% Write and 90% Read  --- ### Transaction size 100,000/100 to 10/1,000,000 <img heihgt="500px" width="600px" src="https://hackmd.io/_uploads/Skg_PZLsa.png" /> --- ### CPU Usage  --- ### Absolute performance  --- # Tenacious Zebra :confetti_ball: ---  https://github.com/barmettlerl/tenacious-zebra --- We have shown: - It is possible to make zebra persistent - It is possible to do it without loosing too much performance --- # Questions :question: ---