Re: XID formatting and SLRU refactorings (was: Add 64-bit XIDs into PostgreSQL 15)

On Mon, Nov 6, 2023 at 3:42 PM Pavel Borisov <pashkin.elfe@gmail.com> wrote:
>
> On Mon, 6 Nov 2023 at 17:07, Alexander Korotkov <aekorotkov@gmail.com> wrote:
> > On Wed, Jul 5, 2023 at 4:46 PM Aleksander Alekseev <aleksander@timescale.com> wrote:
> > > PFE the corrected patchset v58.
> >
> > I'd like to revive this thread.
> >
> > This patchset is extracted from a larger patchset implementing 64-bit xids.  It converts page numbers in SLRUs into
64bits.  The most SLRUs save the same file naming scheme, thus their on-disk representation remains the same.  However,
thepatch 0002 converts pg_notify to actually use a new naming scheme.  Therefore pg_notify can benefit from
simplificationand getting rid of wraparound. 
> >
> > -#define TransactionIdToCTsPage(xid) \
> > -   ((xid) / (TransactionId) COMMIT_TS_XACTS_PER_PAGE)
> > +
> > +/*
> > + * Although we return an int64 the actual value can't currently exceeed 2**32.
> > + */
> > +static inline int64
> > +TransactionIdToCTsPage(TransactionId xid)
> > +{
> > +   return xid / (int64) COMMIT_TS_XACTS_PER_PAGE;
> > +}
> >
> > Is there any reason we transform macro into a function?  If not, I propose to leave this as a macro.  BTW, there is
atypo in a word "exceeed". 
> If I remember right, the compiler will make equivalent code from
> inline functions and macros, and functions has an additional benefit:
> the compiler will report type mismatch if any. That was the only
> reason.

Then it's OK to leave it as an inline function.

> Also, I looked at v58-0001 and don't quite agree with mentioning the
> authors of the original 64-xid patch, from which the current patch is
> derived, as just "privious input" persons.

+1, for converting all "previous input" persons as additional authors.
That would be a pretty long list of authors though.

BTW, I'm a bit puzzled on who should be the first author now?

------
Regards,
Alexander Korotkov