Обсуждение: pgsql: Tweak TOAST code so that columns marked with MAIN storage

Log Message:
-----------
Tweak TOAST code so that columns marked with MAIN storage strategy are
not forced out-of-line unless that is necessary to make the row fit on a
page.  Previously, they were forced out-of-line if needed to get the row
down to the default target size (1/4th page).

Kevin Grittner

Modified Files:
--------------
    pgsql/doc/src/sgml:
        storage.sgml (r1.29 -> r1.30)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/storage.sgml?r1=1.29&r2=1.30)
    pgsql/src/backend/access/heap:
        tuptoaster.c (r1.93 -> r1.94)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/heap/tuptoaster.c?r1=1.93&r2=1.94)
    pgsql/src/include/access:
        tuptoaster.h (r1.43 -> r1.44)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/access/tuptoaster.h?r1=1.43&r2=1.44)