2006/5/18, Andrew Sullivan <ajs@crankycanuck.ca>:
> On Thu, May 18, 2006 at 05:43:19PM +0200, Guillaume Lelarge wrote:
> > Do you mean that, using "alter table test add column" with the "after"
> > option, MySQL creates a new table, populates it with the old table
> > data and finally drops the old table ? I mean, there's the same
> > performance problem with big tables ?
>
> MySQL does that for a great deal of its DDL. Yes, the performance is
> awful for this on big tables.
>
> The reason I didn't answer the OP's question, though, is that I can't
> think of a legitimate reason to do this anyway. The physical layout
> of the columns should not be of concern to the developer, who should
> be naming the columns anyway.
>
I totally agree on the physical layout. Just being curious :)
--
Guillaume.