Re: doc review for parallel vacuum - Mailing list pgsql-hackers

On Tue, 7 Apr 2020 at 13:55, Justin Pryzby <pryzby@telsasoft.com> wrote:
>
> On Tue, Apr 07, 2020 at 09:57:46AM +0530, Amit Kapila wrote:
> > On Mon, Mar 23, 2020 at 10:34 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > On Sun, Mar 22, 2020 at 7:48 AM Justin Pryzby <pryzby@telsasoft.com> wrote:
> > > >
> > > > Original, long thread
> > > >
https://www.postgresql.org/message-id/flat/CAA4eK1%2Bnw1FBK3_sDnW%2B7kB%2Bx4qbDJqetgqwYW8k2xv82RZ%2BKw%40mail.gmail.com#b1745ee853b137043e584b500b41300f
> > > >
> > >
> > > I have comments/questions on the patches:
> > > doc changes
> > > -------------------------
> > > 1.
> > >       <para>
> > > -      Perform vacuum index and cleanup index phases of <command>VACUUM</command>
> > > +      Perform vacuum index and index cleanup phases of <command>VACUUM</command>
> > >
> > > Why is the proposed text improvement over what is already there?
> >
> > I have kept the existing text as it is for this case.
>
> Probably it should say "index vacuum and index cleanup", which is also what the
> comment in vacuumlazy.c says.
>
> > > 2.
> > > If the
> > > -      <literal>PARALLEL</literal> option is omitted, then
> > > -      <command>VACUUM</command> decides the number of workers based on number
> > > -      of indexes that support parallel vacuum operation on the relation which
> > > -      is further limited by <xref
> > > linkend="guc-max-parallel-workers-maintenance"/>.
> > > -      The index can participate in a parallel vacuum if and only if the size
> > > +      <literal>PARALLEL</literal> option is omitted, then the number of workers
> > > +      is determined based on the number of indexes that support parallel vacuum
> > > +      operation on the relation, and is further limited by <xref
> > > +      linkend="guc-max-parallel-workers-maintenance"/>.
> > > +      An index can participate in parallel vacuum if and only if the size
> > >        of the index is more than <xref
> > > linkend="guc-min-parallel-index-scan-size"/>.
> > >
> > > Here, it is not clear to me why the proposed text is better than what
> > > we already have?
> > Changed as per your suggestion.
>
> To answer your question:
>
> "VACUUM decides" doesn't sound consistent with docs.
>
> "based on {+the+} number"
> => here, you're veritably missing an article...
>
> "relation which" technically means that the *relation* is "is further limited
> by"...
>
> > > Patch changes
> > > -------------------------
> > > 1.
> > > - * and index cleanup with parallel workers unless the parallel vacuum is
> > > + * and index cleanup with parallel workers unless parallel vacuum is
> > >
> > > As per my understanding 'parallel vacuum' is a noun phrase, so we
> > > should have a determiner before it.
> >
> > Changed as per your suggestion.
>
> Thanks (I think you meant an "article").
>
> > > - * We allow each worker to update it as and when it has incurred any cost and
> > > + * We allow each worker to update it AS AND WHEN it has incurred any cost and
> > >
> > > I don't see why it is necessary to make this part bold?  We are using
> > > it at one other place in the code in the way it is used here.
> > >
> >
> > Kept the existing text as it is.
>
> I meant this as a question.  I'm not sure what "as and when means" ?  "If and
> when" ?
>
> > I have combined both of your patches.  Let me know if you have any
> > more suggestions, otherwise, I am planning to push this tomorrow.
>
> In the meantime, I found some more issues, so I rebased on top of your patch so
> you can review it.
>

I don't have comments on your change other than the comments Amit
already sent. Thank you for reviewing this part!

Regards,

-- 
Masahiko Sawada            http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services