Both the 7.4.x docs and the 8.0.x docs state:
"This option can only be set at server start or in the postgresql.conf
file."
Perhaps I've been misunderstanding the "or" clause? Does the "or"
clause refer to the fact that it can be sent as an option at server
start or changed with a HUP from postgresql.conf but not set per
connection? Somehow it's always escaped my attention that there were so
many options that distinguished between "server start" and "server
start or in postgresql.conf".
Regardless, having thought about it more, I understand why it would be
impossible to set per connection. I was thinking more about the utility
of having a knob that could be twisted in the circumstances of large
data loads than the reality of what that would mean from the point of
view of WAL and checkpoints.
-tfo
--
Thomas F. O'Connell
Co-Founder, Information Architect
Sitening, LLC
http://www.sitening.com/
110 30th Avenue North, Suite 6
Nashville, TN 37203-6320
615-260-0005
On Mar 22, 2005, at 9:49 PM, Tom Lane wrote:
> "Thomas F.O'Connell" <tfo@sitening.com> writes:
>> Instinctively, it seems like it would be nice to have something
>> similar
>> for checkpoint_timeout, but is there any disadvantage to having a
>> value
>> "dramatically" higher than the default for general use, considering
>> that checkpoint_timeout can only be set at server start?
>
> Huh? IIRC you can change all the checkpoint parameters with SIGHUP.
> You can *not* set them per-connection, that just doesn't make any
> physical sense considering that the behavior involved is cluster-wide.
>
> I doubt that checkpoint_timeout is very important to raise anyway.
> Now checkpoint_segments is something you might well need to raise...
>
> regards, tom lane