Re: pgsql: Parameter toast_tuple_target controls TOAST for new rows

On 2017-11-19 19:08:48 -0500, Simon Riggs wrote:
> On 19 November 2017 at 17:52, Simon Riggs <simon@2ndquadrant.com> wrote:
> > Parameter toast_tuple_target controls TOAST for new rows
> >
> > Specifies the point at which we try to move long column values
> > into TOAST tables.
> >
> > No effect on existing rows.
> >
> > Discussion: https://postgr.es/m/CANP8+jKsVmw6CX6YP9z7zqkTzcKV1+Uzr3XjKcZW=2Ya00OyQQ@mail.gmail.com
> >
> > Author: Simon Riggs <simon@2ndQudrant.com>
> > Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndQuadrant.com>
> >
> > Branch
> > ------
> > master
> >
> > Details
> > -------
> > https://git.postgresql.org/pg/commitdiff/c2513365a0a85e77d3c21adb92fe12cfbe0d1897
> >
> > Modified Files
> > --------------
> > doc/src/sgml/ref/alter_table.sgml      |  2 +-
> > doc/src/sgml/ref/create_table.sgml     | 21 +++++++++++++++
> > src/backend/access/common/reloptions.c | 12 +++++++++
> > src/backend/access/heap/tuptoaster.c   |  2 +-
> > src/include/utils/rel.h                |  9 +++++++
> > src/test/regress/expected/strings.out  | 47 ++++++++++++++++++++++++++++++++++
> > src/test/regress/sql/strings.sql       | 19 ++++++++++++++
> > 7 files changed, 110 insertions(+), 2 deletions(-)
> 
> Am investigating the few buildfarm failures

The tests look very sensitive to differences in tuple size due to
different alignment requirements. Dependant on what MAXALIGN (and some
others) is the number of tuples fitting on a page will differ.

Greetings,

Andres Freund