Post by TUMuchData

📊 𝗝𝘂𝗹𝘆 𝟮, 𝟮𝟬𝟮𝟲: 𝗦𝗰𝗵𝗲𝗺𝗮 𝗖𝗵𝗮𝗻𝗴𝗲 𝗪𝗶𝘁𝗵𝗼𝘂𝘁 𝗦𝘁𝗼𝗽𝗽𝗶𝗻𝗴 𝘁𝗵𝗲 𝗪𝗼𝗿𝗹𝗱: 𝗙𝗿𝗼𝗺 𝗚𝗼𝗼𝗴𝗹𝗲'𝘀 𝗙𝟭 𝗦𝗰𝗵𝗲𝗺𝗮-𝗖𝗵𝗮𝗻𝗴𝗲 𝗣𝗮𝗽𝗲𝗿 𝘁𝗼 𝗢𝗽𝗲𝗻 𝗦𝗼𝘂𝗿𝗰𝗲 𝗧𝗶𝗗𝗕 𝗶𝗻 𝗣𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻 📊: ✨ In this industry talk, Mattias Jonsson will walk you through the process of implementing Google’s pioneering paper, about "Online, Asynchronous Schema Change", in TiDB, powered by PingCAP. You'll learn why each intermediate schema state is essential and what can go wrong if a state is skipped. The session will also explore the interplay between asynchronous schema changes and garbage collection in distributed databases. 🍕 And this talk only: We will provide some 𝗽𝗶𝘇𝘇𝗮 too! 📄 𝗚𝗼𝗼𝗴𝗹𝗲'𝘀 𝗣𝗮𝗽𝗲𝗿: https://lnkd.in/eHQm-Dcp 👩🏻‍💻 𝗧𝗶𝗗𝗕: https://lnkd.in/eMWVHsB 📖 𝗧𝗮𝗹𝗸 𝗔𝗯𝘀𝘁𝗿𝗮𝗰𝘁: In 2013, Google published "Online, Asynchronous Schema Change in F1", describing how a distributed SQL database can evolve its schema without global locks or downtime, by transitioning through a sequence of compatible intermediate states (delete‑only, write‑only, …, public) under a bounded schema lease. TiDB, an open‑source distributed SQL database, is heavily inspired by F1 and Spanner. Taking the paper as our shared starting point, I'll reconstruct why each intermediate state is necessary, deriving them by working backwards from the final "public" state until nothing more can be removed, and show why skipping a state corrupts an index. One question worth discussing: in a database that gives you strongly consistent, ACID data, can the schema be eventually consistent? Different nodes act on different schema versions at the same moment, reconciled only by a bounded lease. What are the pros and cons? 🙋 Mattias Jonsson, Principal Software Engineer at TiDB, powered by PingCAP, brings 𝗼𝘃𝗲𝗿 𝟭𝟱 𝘆𝗲𝗮𝗿𝘀 𝗼𝗳 𝗱𝗮𝘁𝗮𝗯𝗮𝘀𝗲 𝗲𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴 𝗲𝘅𝗽𝗲𝗿𝗶𝗲𝗻𝗰𝗲 from high‑scale environments like Booking.com. 🤩 Join the TUMuchData community for a networking session with like‑minded database enthusiasts!