Making a varchar bigger

Specificaly I am looking at executing something like this:

UPDATE pg_attribute SET atttypmod = 16 where attname = 'x' AND attrelid =
(select pg_class.oid from pg_class where relname = 'mytable');

On December 23, 2004 05:13 pm, Derik Barclay wrote:

Hello Group,

I've run into a bit of a problem, I have a varchar(6) field that I now need
to have as a varchar(12).

I am relatively new to postgres and am unsure how best to do this. What I
would like to do is alter the meta-data directly. Change the value of
atttypmod in pg_attribute directly. Initial tests look good, however I am
unsure how safe this is. Or what else needs to be done? does it need to be
re-indexed?

I have looked at the sections on renaming/changing columns, though this is
more a solid an option, I am dealing with millions of records and the
downtime for the backfill is not acceptable.

I found some old post in here hinting at doing this, however the links in
them are now dead.

-- 
Givex - http://www.givex.com/
Derik Barclay <dbarclay@givex.com>, Systems Software Engineer
+1 416 350 9660
+1 416 250 9661 (fax)

Derik Barclay <dbarclay@givex.com> writes:

Specificaly I am looking at executing something like this:
UPDATE pg_attribute SET atttypmod = 16 where attname = 'x' AND attrelid =
(select pg_class.oid from pg_class where relname = 'mytable');

If you have any indexes or views referencing this column, then it's a
bit harder. But for the table itself I believe that will work.

regards, tom lane

It is combined with another field to form an index.
Does that mean a re-indexing will be required? or are there other issues?

On December 30, 2004 11:03 pm, Tom Lane wrote:

Derik Barclay <dbarclay@givex.com> writes:

Specificaly I am looking at executing something like this:
UPDATE pg_attribute SET atttypmod = 16 where attname = 'x' AND attrelid =
(select pg_class.oid from pg_class where relname = 'mytable');

If you have any indexes or views referencing this column, then it's a
bit harder. But for the table itself I believe that will work.

regards, tom lane

-- 
Givex - http://www.givex.com/
Derik Barclay <dbarclay@givex.com>, Systems Software Engineer
+1 416 350 9660
+1 416 250 9661 (fax)

Derik Barclay <dbarclay@givex.com> writes:

On December 30, 2004 11:03 pm, Tom Lane wrote:

If you have any indexes or views referencing this column, then it's a
bit harder. But for the table itself I believe that will work.

It is combined with another field to form an index.
Does that mean a re-indexing will be required? or are there other issues?

No, I'm just thinking you should update atttypmod for the index column.

regards, tom lane