Tag
isolation-levels
- Jun 20, 2026 Isolation Levels and the Anomalies They Were Supposed to Prevent Why the SQL standard isolation levels are defined by the anomalies they should exclude, why that definition is incomplete, and what Critic and ARIES work revealed about writes that are visible before they are durable. computing history
- May 10, 2025 First-Committer-Wins Validation in Snapshot Isolation How snapshot isolation validates writes against concurrent committers, why a write-write check is sufficient for its own guarantees, and the serializability it leaves on the table. databases
- Aug 1, 2024 The Read Phenomena Ladder and What Each Isolation Level Still Permits Why the four SQL isolation levels are defined by the anomalies they forbid rather than the guarantees they give, and which anomalies fall through the definitions. databases
- Nov 10, 2023 Conflict Serializability and the Precedence Graph Test How read-write conflicts between concurrent transactions form a directed graph, why a cycle means no equivalent serial order exists, and where the test stops being useful. databases
- Jan 19, 2023 Undo Records and Reconstructing Older Row Versions How engines that keep only the current row in the heap rebuild earlier versions from before-images in undo segments, and what that indirection costs on the read path. databases