Re: [COMMITTERS] pgsql: Allow vacuums to report oldestxmin

On Tue, Mar 28, 2017 at 1:06 AM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> On Sun, Mar 26, 2017 at 2:26 AM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>> On Sun, Mar 26, 2017 at 1:37 AM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>>> On Mon, Mar 6, 2017 at 9:37 PM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>>>> On Fri, Mar 3, 2017 at 10:50 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>>>>> Allow vacuums to report oldestxmin
>>>>>
>>>>> Allow VACUUM and Autovacuum to report the oldestxmin value they
>>>>> used while cleaning tables, helping to make better sense out of
>>>>> the other statistics we report in various cases.
>>>>>
>>>>> Branch
>>>>> ------
>>>>> master
>>>>>
>>>>> Details
>>>>> -------
>>>>> http://git.postgresql.org/pg/commitdiff/9eb344faf54a849898d9be012ddfa8204cfeb57c
>>>>>
>>>>> Modified Files
>>>>> --------------
>>>>> src/backend/commands/vacuumlazy.c | 9 +++++----
>>>>> 1 file changed, 5 insertions(+), 4 deletions(-)
>>>>>
>>>>>
>>>>
>>>> Should we change the example in vacuum.sgml file as well? Attached patch.
>>>
>>> "tuples" in the above should be "row versions"?
>>> We should review not only this line but also all the lines in the example
>>> of VERBOSE output, I think.
>>
>> Right. These verbose log messages are out of date. I ran
>> VACUUM(VERBOSE, ANALYZE) with same scenario as current example as
>> possible. Attached patch updates verbose log messages.
>>
>>
>
> Surprisingly the changes "tuples" -> "row versions" in vacuumlazy.c is
> introduced by commit feb4f44d296b88b7f0723f4a4f3945a371276e0b in 2003.

This is the evidence that no one cares about the details of VACUUM VERBOSE
output example. So I'm tempted to simplify the example (please see the
attached patch) instead of keeping updating the example.

> If this patch is applied, it should back-patch to all supported
> branches.

Not sure if it's worth back-patching that.

Regards,

--
Fujii Masao