Re: correction

On Fri, 2022-05-13 at 16:36 -0400, Bruce Momjian wrote:
> On Wed, May 11, 2022 at 12:36:11PM +0200, Laurenz Albe wrote:
> > On Wed, 2022-05-11 at 00:33 +0000, PG Doc comments form wrote:
> > > The following documentation comment has been logged on the website:
> > >
> > > Page: https://www.postgresql.org/docs/14/transaction-iso.html
> > > Description:
> > >
> > > in this page: https://www.postgresql.org/docs/14/transaction-iso.html
> > >
> > > under the Table 13.1 section, if we search for "phantom reads. Stricter
> > > behavior is permitted by the SQL standard", do we mean "Looser behaviour"?
> >
> > What is meant is "The SQL standard allows an implementation to implement
> > stricter behavior than required by the standard; it only defines the things
> > that are *not* allowed to happen at a certain isolation level.  So it is for
> > example fine for PostgreSQL not to allow dirty reads in READ UNCOMMITTED
> > isolation level."
> >
> > Perhaps this could be rewritten to be clearer; it is indeed easy to
> > misunderstand that sentence.
>
> How is this attached patch's wording?
>
> diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
> index 341fea524a..244694b07f 100644
> --- a/doc/src/sgml/mvcc.sgml
> +++ b/doc/src/sgml/mvcc.sgml
> @@ -277,8 +277,8 @@
>
>     <para>
>      The table also shows that PostgreSQL's Repeatable Read implementation
> -    does not allow phantom reads.  Stricter behavior is permitted by the
> -    SQL standard: the four isolation levels only define which phenomena
> +    does not allow phantom reads.  The SQL standard allows more restrictive
> +    behavior:  the four isolation levels only define which phenomena
>      must not happen, not which phenomena <emphasis>must</emphasis> happen.
>      The behavior of the available isolation levels is detailed in the
>      following subsections.

I think that suffers from the same problem: izt sounds like the standard allows
stricter behavior than PostgreSQL.

How about:

  The table also shows that PostgreSQL's Repeatable Read implementation
  does not allow phantom reads.  That is fine, because the SQL standard only
  specifies which anomalies must <emphasis>not</enphasis> occur at a certain
  isolation level.  It is no problem if an implementation provides higher
  guarantees than required.
  The behavior of the available isolation levels is detailed in the
  following subsections.