MVCC in PostgreSQL

Moin Moin,

actually I received a tweet to a blog post from J. Chris Anderson (CouchDB developer) with title “Fixing HTML 5 Storage”. He is writing about the approaches of implementing a local storage feature to HTML 5 ( Please read his very interesting post at

He was talking about which the best way would be to implement this feature and is concerned about having no locks while storing or reading data. That means that a multi version concurrency control (MVCC) should be implemented (like also in CouchDB).

MVCC was originally introduced by PostgreSQL (edit: apparently by InterBase - thanx to andreas) and this is a really big advantage compared to database systems with out it. There is a very good article written by Joseph Mitchell about how MVCC is working in PostgreSQL. The article was written 2001 but is still up to dat. I ask you to read it under to get an idea what MVCC in PostgreSQL is.

More about MVCC can also be read in the offical PostgreSQL docu under


Published: July 14 2009