Change from BIGINT to INT in prod.

Dear All,

I am trying to change some specific columns on some tables in prod and
looking at the best ways to do it with very minimal downtime.

So when i try running *alter table table_name alter column column_name type
INT; *, it is hanging and starts providing a lock on the table.

I have this option in mind with but with a doubt.

- Stop postgres and application connections
- take a schema dump of the specific tables (it takes few seconds)
- take a complete dump of those table or take just a data dump only (-a
option) -- (This takes 3 to 5 mins)
- drop all the specific tables from prod DB
- restore the schema dump
- run the script to change from BIGINT to INT
- Then restore the data. Since the data will take more than 30 mins to
restore, i wanted to allow the application to start accessing the DB while
the restore is ongoing.

So my question is will it be a good idea to bring back up the DB with
applications connecting and same time restoring the data from those
specific tables?

If this is not a good idea...any suggestions on how i can make these
changes to the LIVE DB with minimal downtime?

Many thanks
Ndoh