Обсуждение: pgsql-server/ oc/src/sgml/runtime.sgml rc/back ...

CVSROOT:    /cvsroot
Module name:    pgsql-server
Changes by:    tgl@svr1.postgresql.org    04/01/21 19:33:34

Modified files:
    doc/src/sgml   : runtime.sgml
    src/backend/optimizer/geqo: geqo_main.c
    src/backend/utils/misc: guc.c postgresql.conf.sample
    src/include/optimizer: geqo.h

Log message:
    Repair error apparently introduced in the initial coding of GUC: the
    default value for geqo_effort is supposed to be 40, not 1.  The actual
    'genetic' component of the GEQO algorithm has been practically disabled
    since 7.1 because of this mistake.  Improve documentation while at it.

tgl@svr1.postgresql.org (Tom Lane) writes:
>     Repair error apparently introduced in the initial coding of GUC: the
>     default value for geqo_effort is supposed to be 40, not 1.  The actual
>     'genetic' component of the GEQO algorithm has been practically disabled
>     since 7.1 because of this mistake.

Is this worth considering for a backport to the 7.4 branch?

-Neil

Neil Conway <neilc@samurai.com> writes:
> tgl@svr1.postgresql.org (Tom Lane) writes:
>> Repair error apparently introduced in the initial coding of GUC: the
>> default value for geqo_effort is supposed to be 40, not 1.  The actual
>> 'genetic' component of the GEQO algorithm has been practically disabled
>> since 7.1 because of this mistake.

> Is this worth considering for a backport to the 7.4 branch?

Considering it's been broken for several releases and no one noticed,
I'm not sure it's critical.  This is just something I noticed while
looking at Mike's recent complaint that GEQO is too slow.  This change
actually makes it slower :-( but I'm hoping to find that we can buy
that back with other improvements.

            regards, tom lane