My understanding is that the background reason for your question is how to deploy DB structure changes DB onto production with minimal downtime. For that I'd go with a Blue Green Deployments 1 .

After your comments I assume that you already have running instance of PostgreSQL and would like to modify the content of the DB by altering file structure directly on a "disk" (in this case PVC).

Modifying data structure directly on disk is not the best idea if we are speaking about data integrity, etc.

The reasons for that statement are explained in this article 2. It describes how exactly postgreSQL stores data on disk.

PostgreSQL (by default) writes blocks of data (what PostgreSQL calls pages) to disk in 8k chunks.

Additionally, there is a relation between table and file_path, so postgresql knows which exactly file stores which table.

SELECT pg_relation_filepath('test_data');  
pg_relation_filepath  
----------------------  
base/20886/186770

In this example the file /database/base/20866/186770 contains the actual data for the table test_data.

What is the right way to update the database instead of logging in to the pod and running queries

However, if you sure that you have complete set of files for the DB to operate (like the one you are using during pg_dump / pg_restore) you can try placing that data on another PVC and recreate pod, however that will still result in a downtime.

Hope that helps.