as those for inherited columns; that is, it's no longer allowed for a child
table to not have a check constraint matching one that exists on a parent.
This satisfies the principle of least surprise (rows selected from the parent
will always appear to meet its check constraints) and eliminates some
longstanding bogosity in pg_dump, which formerly had to guess about whether
check constraints were really inherited or not.
The implementation involves adding conislocal and coninhcount columns to
pg_constraint (paralleling attislocal and attinhcount in pg_attribute)
and refactoring various ALTER TABLE actions to be more like those for
columns.
Alex Hunsaker, Nikhil Sontakke, Tom Lane
columns, and the new version can be stored on the same heap page, we no longer
generate extra index entries for the new version. Instead, index searches
follow the HOT-chain links to ensure they find the correct tuple version.
In addition, this patch introduces the ability to "prune" dead tuples on a
per-page basis, without having to do a complete VACUUM pass to recover space.
VACUUM is still needed to clean up dead index entries, however.
Pavan Deolasee, with help from a bunch of other people.
named pg_toast_temp_nnn, alongside the pg_temp_nnn schemas used for the temp
tables themselves. This allows low-level code such as the relcache to
recognize that these tables are indeed temporary, which enables various
optimizations such as not WAL-logging changes and using local rather than
shared buffers for access. Aside from obvious performance benefits, this
provides a solution to bug #3483, in which other backends unexpectedly held
open file references to temporary tables. The scheme preserves the property
that TOAST tables are not in any schema that's normally in the search path,
so they don't conflict with user table names.
initdb forced because of changes in system view definitions.
This commit breaks any code that assumes that the mere act of forming a tuple
(without writing it to disk) does not "toast" any fields. While all available
regression tests pass, I'm not totally sure that we've fixed every nook and
cranny, especially in contrib.
Greg Stark with some help from Tom Lane
per-column options for btree indexes. The planner's support for this is still
pretty rudimentary; it does not yet know how to plan mergejoins with
nondefault ordering options. The documentation is pretty rudimentary, too.
I'll work on improving that stuff later.
Note incompatible change from prior behavior: ORDER BY ... USING will now be
rejected if the operator is not a less-than or greater-than member of some
btree opclass. This prevents less-than-sane behavior if an operator that
doesn't actually define a proper sort ordering is selected.
created in the bootstrap phase proper, rather than added after-the-fact
by initdb. This is cleaner than before because it allows us to retire the
undocumented ALTER TABLE ... CREATE TOAST TABLE command, but the real reason
I'm doing it is so that toast tables of shared catalogs will now have
predetermined OIDs. This will allow a reasonably clean solution to the
problem of locking tables before we load their relcache entries, to appear
in a forthcoming patch.
