Exploration ·
How a database survives a crash
Pull the plug on a database halfway through a write and it comes back with every committed transaction and none of the half-finished ones. How? Follow a write through the log, the buffer pool and the disk, compare B+trees with LSM-trees, watch compaction, and then see the other half of the promise — what concurrent transactions are allowed to see — with real PostgreSQL and SQLite running between the paragraphs.