| From: | Ow Mun Heng <Ow(dot)Mun(dot)Heng(at)wdc(dot)com> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
| Cc: | Mario Weilguni <mweilguni(at)sime(dot)com>, Pgsql performance <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Altering a column type - Most efficient way |
| Date: | 2008-07-11 02:17:00 |
| Message-ID: | 1215742620.853.10.camel@neuromancer.home.net |
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| Lists: | pgsql-performance |
On Thu, 2008-07-10 at 09:57 -0400, Alvaro Herrera wrote:
> Ow Mun Heng wrote:
>
> > This is what I see on the table
> >
> > NEW attypmod = -1
> > OLD attypmod = 8
>
> 8 means varchar(4) which is what you said you had (4+4)
> -1 means unlimited size.
>
This is cool.
If it were this simple a change, I'm not certain why (I believe) PG is
checking each and every row to see if it will fit into the new column
definition/type.
Thus, I'm still a bit hesitant to do the change, although it is
definitely a very enticing thing to do. ( I presume also that this
change will be instantaneous and does not need to check on each and
every row of the table?)
Thanks./
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