How to improve add column query from large table using python psycopg2

Question

I am using following command to add the new column in existing large table in postgresql.

alter table table_name add column column_name bigserial

Is there any way to increase the performance of above query on large table?

Answer 1

to reduce lock time, you can:

alter table table_name add column column_name bigint;
create sequence seq_name;
with c as (select * from table_name) 
  update table_name set column_name = nextval('seq_name'::regclass);

alter table table_name alter column column_name set default nextval('seq_name');