Steve Wampler wrote:
> I can see two easy approaches (feel free to suggest better ones!):
>
> (a) rename the table as an 'archive' log table and then recreate the
> 'active' log table.
>
> (b) extract the old log information into an archive table,
> removing it from the original
>
> I like (b), personally, but would like to know if anyone
> sees any "gotcha's", especially w.r.t. postgresql as the
> database system.
>
if you vacuum on a regular basis, (b) shouldn't be a problem. right
now, postgres won't reuse the deleted pages unless you vacuum it. your
table will balloon until you do a vacuum. ideally you should be able to
do (a) in a transaction, but i'd have some concern if table
renaming/creation is in fact isolated in the transaction.
if you're worried about having the table unavailable, though (even for a
split second), i don't know if either one would work well for you if
you're needing to update the table during a vacuum. you may want to
approach it in the application where you have the application log to
tables named for the date or week # (e.g., log_20000526). you can then
play with the log files at your leisure.
jeff
