| From: | Andrew Sullivan <ajs(at)crankycanuck(dot)ca> |
|---|---|
| To: | pgsql-sql(at)postgresql(dot)org |
| Subject: | Re: Add column and specify the column position in a table |
| Date: | 2006-05-18 15:58:29 |
| Message-ID: | 20060518155829.GE29472@phlogiston.dyndns.org |
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| Lists: | pgsql-sql |
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.
A
--
Andrew Sullivan | ajs(at)crankycanuck(dot)ca
The whole tendency of modern prose is away from concreteness.
--George Orwell
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