Episode 496: Bruce Momjian on Multi-Model Concurrency Management in Postgres (MVCC) : Software program Engineering Radio

This week, Postgres server developer Bruce Momjian joins host Robert Blumen for a dialogue of multi-version concurrency management (MVCC) within the Postgres database. They start with a dialogue of the isolation requirement in database transactions (I in ACID); how isolation could be achieved with locking; limitations of locking; how locking limits concurrency and creates variability in question runtimes; multi-version concurrency management as a method to attain isolation; how Postgres manages a number of variations of a row; snapshots; copy-on-write and snapshots; visibility; database transaction IDs; how tx ids, snapshots and variations work together; the necessity for locking when there are a number of writers; how MVCC was added to Postgres; and how one can clear up unused area left over from aged-out variations.

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SE Radio theme music: “Damaged Actuality” by Kevin MacLeod (incompetech.com)
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