Re: WAL Log Size

On Fri, Feb 29, 2008 at 1:08 AM, Greg Smith <gsmith(at)gregsmith(dot)com> wrote:
> On Fri, 29 Feb 2008, Sam Mason wrote:
>
> > Just out of interest, why doesn't it do the following?
> >
> > BEGIN;
> > create table xlog_switch as
> > select '0123456789ABCDE' from generate_series(1,1000000);
> > ROLLBACK;
>
> I'm not 100% sure here what happens when you do the above, and it depends
> on version, but there are cases where creating a new or empty table in a
> transaction is optimized to not create any WAL as a performance
> improvement. This has become a common idiom for that reason:

That's why the create table statement up there had the from
generate_series bit...