Introduction Last week, Burkhard Graves asked me to answer the following StackOverflow question: And, since he wasn’t convinced about my answer: I decided to turn it into a dedicated article and explain how UPSERT and MERGE work in the top 4 most common relational database systems: Oracle, SQL Server, PostgreSQL, and MySQL. Domain Model For … Continue reading How do UPSERT and MERGE work in Oracle, SQL Server, PostgreSQL and MySQL →

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With TokuDB v6.6 out now, I’m excited to present one of my favorite enhancements: fast updates with TokuDB. Update intensive applications can have their throughput limited by the random read capacity of the storage system. The cause of the throughput limit is the read-modify-write algorithm that MySQL uses when processing update statements. MySQL reads a row from the storage engine, applies the updates to it, and then writes the new row to the storage engine. To address this throughput limit, TokuDB uses a different update algorithm that simply encodes the update expressions of the SQL statement into tiny programs that are stored in an update Fractal Tree® message. This update message is injected into the root of the Fractal Tree index. …