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

On Thu, Jan 25, 2018 at 10:56 AM, Claudio Freire <klaussfreire(at)gmail(dot)com> wrote:
> 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

I had the tests running in a loop all day long, and I cannot reproduce
that variance.

Can you share your steps to reproduce it, including configure flags?