Re: COPY .. FREEZE, (apparently) not working on 9.6

On 2017-04-26 01:40:40 +0200, Danilo Olivares wrote:
> Hello,
>
> While testing "COPY/ FREEZE" feature, I've found a weird issue, by which I
> am unable to actually freeze the rows/tables when using psql 9.6. Or, at
> least, so it looks when inspecting 'xmin'..
>
> Here is the actual (failing) output from running a simple COPY/FREEZE
> snippet against postgres 9.6.2 (x86_64) on CentOS:
>
> # /usr/pgsql-9.6/bin/psql -U postgres -h localhost
> postgres=# BEGIN;
> BEGIN
> postgres=# CREATE TABLE da (text text);
> CREATE TABLE
> postgres=# COPY da FROM STDIN WITH (DELIMITER ',', FREEZE);
> sample
> \.
> COPY 1
> postgres=# COMMIT;
> COMMIT
> postgres=# select xmin,xmax from da;
> xmin | xmax
> —----+------
> 1679 | 0
> (1 row)

These days xmin still shows the pre-frozen value, even if a tuple is
frozen. That's for forensic purposes, so we can freeze more
aggressively. You'd have to use the pageinspect extension to verify
whether it's actually frozen.

- Andres