Andrew Sullivan wrote:
On Wed, Jun 06, 2007 at 04:04:44PM -0600, Dan Harris wrote:
of these operations or a full dump/reload. I do run VACUUM regularly, it's
just that sometimes we need to go back and update a huge percentage of rows
in a single batch due to changing customer requirements, leaving us with
significant table bloat.
Do you need to update those rows in one transaction (i.e. is the
requirement that they all get updated such that the change only
becomes visible at once)? If not, you can do this in batches and
vacuum in between. Batch updates are the prime sucky area in
Postgres.
They don't always have to be in a single transaction, that's a good idea to
break it up and vacuum in between, I'll consider that. Thanks
Another trick, if the table is otherwise mostly static, is to do the
updating in a copy of the table, and then use the transactional DDL
features of postgres to change the table names.
I thought of this, but it seems to break other application logic that feeds a
steady streams of inserts into the tables.
Thanks again for your thoughts. I guess I'll just have to work around this
problem in application logic.
