Horton

Re: WAL usage calculation patch

Amit Kapila <amit.kapila16@gmail.com>

View thread
From: Amit Kapila <amit.kapila16@gmail.com>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>, Dilip Kumar <dilipbalaut@gmail.com>, Julien Rouhaud <rjuju123@gmail.com>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, Fujii Masao <masao.fujii@oss.nttdata.com>, Kirill Bychik <kirill.bychik@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Thomas Munro <thomas.munro@gmail.com>
Date: 2020-04-14T03:57:18Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Change the display of WAL usage statistics in Explain.

  2. Cosmetic fixups for WAL usage work.

  3. Allow parallel create index to accumulate buffer usage stats.

  4. Allow autovacuum to log WAL usage statistics.

  5. Add the option to report WAL usage in EXPLAIN and auto_explain.

  6. Allow pg_stat_statements to track WAL usage statistics.

  7. Add infrastructure to track WAL usage.

  8. Include information on buffer usage during planning phase, in EXPLAIN output, take two.

  9. Include information on buffer usage during planning phase, in EXPLAIN output.

  10. Allow parallel vacuum to accumulate buffer usage.

  11. Allow pg_stat_statements to track planning statistics.

On Wed, Apr 8, 2020 at 8:36 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Tue, Apr 7, 2020 at 3:30 PM Peter Eisentraut
> <peter.eisentraut@2ndquadrant.com> wrote:
> >
> >
> > We also have existing cases for the other way:
> >
> >      actual time=0.050..0.052
> >      Buffers: shared hit=3 dirtied=1
> >
>
> Buffers case is not the same because 'shared' is used for 'hit',
> 'read', 'dirtied', etc.  However, I think it is arguable.
>
> > The cases mentioned by Justin are not formatted in a key=value format,
> > so it's not quite the same, but it also raises the question why they are
> > not.
> >
> > Let's figure out a way to consolidate this without making up a third format.
> >
>
> Sure, I think my intention is to keep the format of WAL stats as close
> to Buffers stats as possible because both depict I/O and users would
> probably be interested to check/read both together.  There is a point
> to keep things in a format so that it is easier for someone to parse
> but I guess as these as fixed 'words', it shouldn't be difficult
> either way and we should give more weightage to consistency.  Any
> suggestions?
>

Peter E, others, any suggestions on how to move forward?  I think here
we should follow the rule "follow the style of nearby code" which in
this case would be to have one space after each field as we would like
it to be closer to the "Buffers" format.  It would be good if we have
a unified format among all Explain stuff but we might not want to
change the existing things and even if we want to do that it might be
a broader/bigger change and we should do that as a PG14 change.  What
do you think?

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com