Horton

Re: making relfilenodes 56 bits

Hannu Krosing <hannuk@google.com>

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From: Hannu Krosing <hannuk@google.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Dilip Kumar <dilipbalaut@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Thomas Munro <thomas.munro@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-07-12T21:00:22Z
Lists: pgsql-hackers 
Re: staticAssertStmt(MAX_FORKNUM <= INT8_MAX);

Have you really thought through making the ForkNum 8-bit ?

For example this would limit a columnar storage with each column
stored in it's own fork (which I'd say is not entirely unreasonable)
to having just about ~250 columns.

And there can easily be other use cases where we do not want to limit
number of forks so much

Cheers
Hannu

On Tue, Jul 12, 2022 at 10:36 PM Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Tue, Jul 12, 2022 at 1:09 PM Andres Freund <andres@anarazel.de> wrote:
> > What does currently happen if we exceed that?
>
> elog
>
> > > diff --git a/src/include/utils/wait_event.h b/src/include/utils/wait_event.h
> > > index b578e2ec75..5d3775ccde 100644
> > > --- a/src/include/utils/wait_event.h
> > > +++ b/src/include/utils/wait_event.h
> > > @@ -193,7 +193,7 @@ typedef enum
> > >       WAIT_EVENT_LOGICAL_REWRITE_TRUNCATE,
> > >       WAIT_EVENT_LOGICAL_REWRITE_WRITE,
> > >       WAIT_EVENT_RELATION_MAP_READ,
> > > -     WAIT_EVENT_RELATION_MAP_SYNC,
> > > +     WAIT_EVENT_RELATION_MAP_RENAME,
> >
> > Very minor nitpick: To me REPLACE would be a bit more accurate than RENAME,
> > since it includes fsync etc?
>
> Sure, I had it that way for a while and changed it at the last minute.
> I can change it back.
>
> --
> Robert Haas
> EDB: http://www.enterprisedb.com
>
>

Commits

  1. Fix typos in comments, code and documentation

  2. Increase width of RelFileNumbers from 32 bits to 56 bits.

  3. Move RelFileNumber declarations to common/relpath.h.

  4. Include RelFileLocator fields individually in BufferTag.

  5. Convert macros to static inline functions (buf_internals.h)

  6. Remove the restriction that the relmap must be 512 bytes.

  7. Change internal RelFileNode references to RelFileNumber or RelFileLocator.

  8. Reorder subskiplsn in pg_subscription to avoid alignment issues.

  9. Fix DROP {DATABASE,TABLESPACE} on Windows.

  10. Restructure smgr API as per recent proposal. smgr no longer depends on