Re: Table rewrites vs. pending AFTER triggers

On Thu, Jan 03, 2008 at 01:08:47PM +0530, Gokulakannan Somasundaram wrote:

> Can you please explain, any specific use-case where DDLs are necessary
> within a transaction?

I don't think they are ever necessary, they're just very very nice. For
example:

- You want a new column to appear populated  on a table atomically. You
do a BEGIN; add column; update set column=foo; add foreign key; COMMIT
- Installation of external modules can be done atomically, so you don't
end up with half installed contrib modules.
- Principle of Least Surprise. Automatic commit for any reason seems
wrong.
- Temporarily disabling triggers/indexes/constraints, if the system
aborts/crashes, the triggers are reinstated automatically.
- Just general niceity of being able to test schema changes without
immediatly changing the system.

There are many more...