In particular, there was a mathematical tie between the two possible
nestloop-with-materialized-inner-scan plans for a join (ie, we computed
the same cost with either input on the inside), resulting in a roundoff
error driven choice, if the relations were both small enough to fit in
sort_mem. Add a small cost factor to ensure we prefer materializing the
smaller input. This changes several regression test plans, but with any
luck we will now have more stability across platforms.
* ALTER ... ADD COLUMN with defaults and NOT NULL constraints works per SQL
spec. A default is implemented by rewriting the table with the new value
stored in each row.
* ALTER COLUMN TYPE. You can change a column's datatype to anything you
want, so long as you can specify how to convert the old value. Rewrites
the table. (Possible future improvement: optimize no-op conversions such
as varchar(N) to varchar(N+1).)
* Multiple ALTER actions in a single ALTER TABLE command. You can perform
any number of column additions, type changes, and constraint additions with
only one pass over the table contents.
Basic documentation provided in ALTER TABLE ref page, but some more docs
work is needed.
Original patch from Rod Taylor, additional work from Tom Lane.
- LIKE <subtable> [ INCLUDING DEFAULTS | EXCLUDING DEFAULTS ]
- Quick cleanup of analyze.c function prototypes.
- New non-reserved keywords (INCLUDING, EXCLUDING, DEFAULTS), SQL 200X
Opted not to extend for check constraints at this time.
As per the definition that it's user defined columns, OIDs are NOT
inherited.
Doc and Source patches attached.
--
Rod Taylor <rbt@rbt.ca>
columns in DefineIndex. So, ALTER TABLE ... PRIMARY KEY will now
automatically add the NOT NULL constraint. It appeared the alter_table
regression test wanted this to occur, as after the change the regression
test better matched in inline 'fails'/'succeeds' comments.
Rod Taylor
and revert documentation to describe the existing INHERITS clause
instead, per recent discussion in pghackers. Also fix implementation
of SQL_inheritance SET variable: it is not cool to look at this var
during the initial parsing phase, only during parse_analyze(). See
recent bug report concerning misinterpretation of date constants just
after a SET TIMEZONE command. gram.y really has to be an invariant
transformation of the query string to a raw parsetree; anything that
can vary with time must be done during parse analysis.
Neil Conway
Bruce Momjian
Tom Lane