The heap is described in 1.3 [1] and MVCC is described in Chapter 5 [2]. I'd also recommend the Postgres docs [3], they aren't quite as accessible as this but

The heap is described in 1.3 [1] and MVCC is described in Chapter 5 [2]. I'd also recommend the Postgres docs [3], they aren't quite as accessible as this but are detailed and overall well-written. [1] https://www.interdb.jp/pg/pgsql01.html#_1.3 https://www.interdb.jp/pg/pgsql01.html#_1.3. [2] https://www.interdb.jp/pg/pgsql05.html https://www.interdb.jp/pg/pgsql05.html [3] https://www.postgresql.org/docs/14/internals.html https://www.postgresql.org/docs/14/internals.html