Bruce Momjian is co-founder and core team member of the PostgreSQL Global Development Group, and has worked on PostgreSQL since 1996. He has been employed by EDB since 2006. He has spoken at many international open-source conferences and is the author of PostgreSQL: Introduction and Concepts, published by Addison-Wesley. Prior to his involvement with PostgreSQL, Bruce worked as a consultant, developing custom database applications for some of the world's largest law firms. As an academic, Bruce holds a Masters in Education, an honorary doctorate, was a high school computer science teacher, and lectures internationally.
The Postgres write-ahead log, or WAL, is basically a change-log for the
database. It enables several important Postgres features: crash
recovery, point-in-time recovery, and binary and logical replication.
This talk explains what is stored in the WAL, how binary and logical
replication work, and how replication slots track replication progress.
Slides at wal.pdf