Horton

Re: WAL usage calculation patch

Julien Rouhaud <rjuju123@gmail.com>

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From: Julien Rouhaud <rjuju123@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Euler Taveira <euler.taveira@2ndquadrant.com>, Dilip Kumar <dilipbalaut@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: 2020-04-10T19:37:54Z
Lists: pgsql-hackers

Commits

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  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 Fri, Apr 10, 2020 at 8:17 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Tue, Apr 7, 2020 at 2:48 PM Julien Rouhaud <rjuju123@gmail.com> wrote:
> >
> > On Tue, Apr 7, 2020 at 4:36 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> > > On Mon, Apr 6, 2020 at 7:58 PM Euler Taveira
> > > <euler.taveira@2ndquadrant.com> wrote:
> > > Few comments:
> > > 1.
> > > - int64 wal_num_fpw; /* # of WAL full page image records generated */
> > > + int64 wal_num_fpw; /* # of WAL full page images generated */
> > >
> > > Let's change comment as " /* # of WAL full page writes generated */"
> > > to be consistent with other places like instrument.h.  Also, make a
> > > similar change at other places if required.
> >
> > Agreed.  That's pg_stat_statements.c and instrument.h.  I'll send a
> > patch once we reach consensus with the rest of the comments.
> >
>
> Would you like to send a consolidated patch that includes Euler's
> suggestion and Justin's patch (by making changes for points we
> discussed.)?  I think we can keep the point related to number of
> spaces before each field open?

Sure, I'll take care of that tomorrow!

> > > 2.
> > >        <entry>
> > > -        Total amount of WAL bytes generated by the statement
> > > +        Total number of WAL bytes generated by the statement
> > >        </entry>
> > >
> > > I feel the previous text was better as this field can give us the size
> > > of WAL with which we can answer "how much WAL data is generated by a
> > > particular statement?".  Julien, do you have any thoughts on this?
> >
> > I also prefer "amount" as it feels more natural.
> >
>
> As we see no other opinion on this matter, we can use "amount" here.

Ok.