Re: pg_upgrade bug found!

Josh Berkus <josh@agliodbs.com> writes:
>> -- It will not lock any tables but will generate I/O.

> add:
> IMPORTANT: Depending on the size and configuration of your database,
> this script may generate a lot of I/O and degrade database performance.
> Users should execute this script during a low traffic period and watch
> the database load.

It might be worth suggesting that people can adjust their vacuum delay
parameters to control the I/O load.
        regards, tom lane