Re: [HACKERS] Vacuum: allow usage of more than 1GB of work mem

On Thu, Jan 25, 2018 at 4:11 AM, Thomas Munro
<thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> On Thu, Jan 18, 2018 at 9:17 AM, Claudio Freire <klaussfreire(at)gmail(dot)com> wrote:
>> Huh. That was simpler than I thought.
>>
>> Attached rebased versions.
>
> Hi Claudio,
>
> FYI the regression test seems to have some run-to-run variation.
> Though it usually succeeds, recently I have seen a couple of failures
> like this:
>
> ========= Contents of ./src/test/regress/regression.diffs
> *** /home/travis/build/postgresql-cfbot/postgresql/src/test/regress/expected/vacuum.out
> 2018-01-24 01:41:28.200454371 +0000
> --- /home/travis/build/postgresql-cfbot/postgresql/src/test/regress/results/vacuum.out
> 2018-01-24 01:51:07.970049937 +0000
> ***************
> *** 128,134 ****
> SELECT pg_relation_size('vactst', 'main');
> pg_relation_size
> ------------------
> ! 0
> (1 row)
>
> SELECT count(*) FROM vactst;
> --- 128,134 ----
> SELECT pg_relation_size('vactst', 'main');
> pg_relation_size
> ------------------
> ! 8192
> (1 row)
>
> SELECT count(*) FROM vactst;
> ======================================================================
>
> --
> Thomas Munro
> http://www.enterprisedb.com

I'll look into it

However, shouldn't an empty relation have an initial page anyway? In
that case shouldn't the correct value be 8192?