Re: Disk Performance Problem on Large DB

On Thu, Nov 4, 2010 at 9:33 PM, Samuel Stearns
<SStearns@internode.com.au> wrote:
> TRUNCATE doesn't generate any rollback data, which makes it lightning fast. It just de-allocates the data pages used
bythe table. 

Also truncate, like nearly everything in pgsql, can be rolled back.  I
still remember showing my oracle co-dbas in my last job freak out when
I showed them things like

begin;
update table yada...
truncate table;
rollback;

or
begin;
drop index xyz;
explain select ...
rollback;

transactable everything is pretty cool. (note database and tablespace
craete / drop are the only things that aren't transactable, which
makes some sense.)