Re: what happens to postmaster?

In response to zach cruise <zachc1980(at)gmail(dot)com>:

> ...when i am importing a table (from oracle, or updating it), and a
> user queries that same table?

I depends on a lot of information you haven't provided ... Is the
update inside a transaction? Have you locked the table?

The real answer is: whatever you want to happen. Depending on how you
set up the import, you have control over how others can interact with
the table while the import is running.

Some examples:
* Grab an access exclusive lock on the table, nobody else will be able
to access it until you're done.
* Grab an exclusive lock on the table, others will be able to read, but not
write to it until you're done.

Some documentation to read up on:
http://www.postgresql.org/docs/8.4/static/explicit-locking.html

> is it ok to be concerned about corruption etc.

You should always be concerned about those things.

--
Bill Moran
http://www.potentialtech.com
http://people.collaborativefusion.com/~wmoran/