PostgreSQL 12 High Availability Cookbook - Third Edition

How it works...

By adding the CONCURRENTLY modifier, PostgreSQL will begin the process of building an index. While it does this, it also tracks the incoming insert, update, and delete activities to include them in the new index.

In the connection where we invoked the CREATE INDEX statement, we will not see a prompt again until PostgreSQL finishes building the index. So, how can we tell it apart from any regular index creation? Well, one of the reasons we built an example was to prove that concurrency is present. The INSERT statement in the second connection should succeed before the index is complete. The process is the same for a production PostgreSQL instance. Any incoming writes to a table undergoing a concurrent index creation will complete ...