Re: Does converting an indexed varchar to text rewrite its index? Docs say so, tests say no.

On 1/23/20 1:28 PM, Mike Lissner wrote:
> You wrote:
>
>  > Well it did not rebuilt the index("t1_name_idx") you created on name.
>
> OK, so then the docs *are* wrong? They say that:
>
> > any indexes on the affected columns must still be rebuilt.
>
> But that doesn't happen? Sorry to be persistent. I'm just a bit confused
> here.

My guess is that it is because in Postgres varchar is just text with an
optional length restriction. I say optional because you can do:

CREATE TABLE t2 (id serial PRIMARY KEY, name varchar);

So as I understand it when you are go from varchar to text you are not
really changing type, just the type oid. I tried searching the source
for confirmation of this to no avail. A definitive answer is going to
need come from someone with more knowledge of the internals.

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com