On Wed, 2022-11-09 at 09:16 -0500, Robert Treat wrote:
> On Mon, Nov 7, 2022 at 5:04 PM Laurenz Albe <[email protected]> wrote:
> > Some comments:
> >
> <snip>
> > > --- a/doc/src/sgml/ref/release_savepoint.sgml
> > > +++ b/doc/src/sgml/ref/release_savepoint.sgml
> > > @@ -34,23 +34,16 @@ RELEASE [ SAVEPOINT ]
> > > <replaceable>savepoint_name</replaceable>
> > > <title>Description</title>
> > >
> > > <para>
> > > - <command>RELEASE SAVEPOINT</command> destroys a savepoint previously
> > > defined
> > > - in the current transaction.
> > > + <command>RELEASE SAVEPOINT</command> will subcommit the subtransaction
> > > + established by the named savepoint, if one exists. This will release
> > > + any resources held by the subtransaction. If there were any
> > > + subtransactions of the named savepoint, these will also be
> > > subcommitted.
> > > </para>
> > >
> > > <para>
> >
> > "Subtransactions of the named savepoint" is somewhat confusing; how about
> > "subtransactions of the subtransaction established by the named savepoint"?
> >
> > If that is too long and explicit, perhaps "subtransactions of that
> > subtransaction".
>
> Personally, I think these are more confusing.
Perhaps. I was worried because everywhere else, the wording makes a clear
distinction
between a savepoint and the subtransaction created by a savepoint. But perhaps
some
sloppiness is better to avoid such word cascades.
> > > --- a/doc/src/sgml/ref/rollback.sgml
> > > +++ b/doc/src/sgml/ref/rollback.sgml
> > > @@ -56,11 +56,14 @@ ROLLBACK [ WORK | TRANSACTION ] [ AND [ NO ] CHAIN ]
> > > <term><literal>AND CHAIN</literal></term>
> > > <listitem>
> > > <para>
> > > - If <literal>AND CHAIN</literal> is specified, a new transaction is
> > > + If <literal>AND CHAIN</literal> is specified, a new unaborted
> > > transaction is
> > > immediately started with the same transaction characteristics (see
> > > <xref
> > > linkend="sql-set-transaction"/>) as the just finished one.
> > > Otherwise,
> > > no new transaction is started.
> >
> > I don't think that is an improvement. "Unaborted" is an un-word. A new
> > transaction
> > is always "unaborted", isn't it?
>
> I thought about this as well when reviewing it, but I do think
> something is needed for the case where you have a transaction which
> has suffered an error and then you issue "rollback and chain"; if you
> just say "a new transaction is immediately started with the same
> transaction characteristics" it might imply to some the new
> transaction has some kind of carry over of the previous broken
> transaction... the use of the word unaborted makes it clear that the
> new transaction is 100% functional.
A new transaction is never aborted in my understanding. Being aborted is not a
characteristic of a transaction, but a state.
> >
>
>
> > > + The internal transaction ID type <type>xid</type> is 32-bits wide
> >
> > There should be no hyphen in "32 bits wide", just as in "3 years old".
>
> Minor aside, we should clean up glossary.sgml as well.
Right, it has this:
The numerical, unique, sequentially-assigned identifier that each
transaction receives when it first causes a database modification.
Frequently abbreviated as <firstterm>xid</firstterm>.
When stored on disk, xids are only 32-bits wide, so only
approximately four billion write transaction IDs can be generated;
to permit the system to run for longer than that,
<firstterm>epochs</firstterm> are used, also 32 bits wide.
Which reminds me that I should have suggested <firstterm> rather than
<quote> where I complained about the use of <literal>.
> >
> > + Up to
> > + 64 open subxids are cached in shared memory for each backend; after
> > + that point, the overhead increases significantly since we must look
> > + up subxid entries in <filename>pg_subtrans</filename>.
> >
> > Comma before "since". Perhaps you should mention that this means disk I/O.
>
> ISTR that you only use a comma before since in cases where the
> preceding thought contains a negative.
Not being a native speaker, I'll leave that to those who are; I went by feeling.
> In any case, are you thinking something like this:
>
> " 64 open subxids are cached in shared memory for each backend; after
> that point the overhead increases significantly due to additional disk I/O
> from looking up subxid entries in <filename>pg_subtrans</filename>."
Yes.
Yours,
Laurenz Albe
