* 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.
so that the 'val' is computed only once, per recent discussion. The
speedup is not much when 'val' is just a simple variable, but could be
significant for larger expressions. More importantly this avoids issues
with multiple evaluations of a volatile 'val', and it allows the CASE
expression to be reverse-listed in its original form by ruleutils.c.
about whether it is applied before or after eval_const_expressions().
I believe there were some corner cases where the system would fail to
recognize that a partial index is applicable because of the previous
inconsistency. Store normal rather than 'implicit AND' representations
of constraints and index predicates in the catalogs.
initdb forced due to representation change of constraints/predicates.
pghackers proposal of 8-Nov. All the existing cross-type comparison
operators (int2/int4/int8 and float4/float8) have appropriate support.
The original proposal of storing the right-hand-side datatype as part of
the primary key for pg_amop and pg_amproc got modified a bit in the event;
it is easier to store zero as the 'default' case and only store a nonzero
when the operator is actually cross-type. Along the way, remove the
long-since-defunct bigbox_ops operator class.
Remove the 'strategy map' code, which was a large amount of mechanism
that no longer had any use except reverse-mapping from procedure OID to
strategy number. Passing the strategy number to the index AM in the
first place is simpler and faster.
This is a preliminary step in planned support for cross-datatype index
operations. I'm committing it now since the ScanKeyEntryInitialize()
API change touches quite a lot of files, and I want to commit those
changes before the tree drifts under me.
with required outer parentheses. Breakage seems to be leftover from
domain-constraint patches. This could be smarter about suppressing
extra parens, but at this stage of the release cycle I want certainty
not cuteness.
in the schema search path. Otherwise pg_dump doesn't correctly dump
scenarios where a custom opclass is created in 'public' and then used
by indexes in other schemas.
Before patch:
test=# select pg_get_constraintdef(oid) from pg_constraint;
pg_get_constraintdef
-------------------------------------------------------------------------------------------------
CHECK (VALUE >= 0)
CHECK ((((a)::text = 'asdf'::text) OR ((a)::text = 'fdsa'::text)) OR
((a)::text = 'dfd'::text))
PRIMARY KEY (b)
FOREIGN KEY (a) REFERENCES test2(b)
UNIQUE (b)
(5 rows)
test=# select pg_get_constraintdef(oid, true) from pg_constraint;
pg_get_constraintdef
-----------------------------------------------------------------------------------
CHECK VALUE >= 0
CHECK a::text = 'asdf'::text OR a::text = 'fdsa'::text OR a::text =
'dfd'::text
PRIMARY KEY (b)
FOREIGN KEY (a) REFERENCES test2(b)
UNIQUE (b)
(5 rows)
After patch:
test=# select pg_get_constraintdef(oid) from pg_constraint;
pg_get_constraintdef
-------------------------------------------------------------------------------------------------
CHECK (VALUE >= 0)
CHECK ((((a)::text = 'asdf'::text) OR ((a)::text = 'fdsa'::text)) OR
((a)::text = 'dfd'::text))
PRIMARY KEY (b)
FOREIGN KEY (a) REFERENCES test2(b)
UNIQUE (b)
(5 rows)
test=# select pg_get_constraintdef(oid, true) from pg_constraint;
pg_get_constraintdef
-----------------------------------------------------------------------------------
CHECK (VALUE >= 0)
` CHECK (a::text = 'asdf'::text OR a::text = 'fdsa'::text OR a::text =
'dfd'::text)
PRIMARY KEY (b)
FOREIGN KEY (a) REFERENCES test2(b)
UNIQUE (b)
(5 rows)
It's important that those brackets are there to (a) match all other
constraints and (b) so that people can just copy and paste them and it
will work as SQL.
Christopher Kings-Lynne
datatype by array_eq and array_cmp; use this to solve problems with memory
leaks in array indexing support. The parser's equality_oper and ordering_oper
routines also use the cache. Change the operator search algorithms to look
for appropriate btree or hash index opclasses, instead of assuming operators
named '<' or '=' have the right semantics. (ORDER BY ASC/DESC now also look
at opclasses, instead of assuming '<' and '>' are the right things.) Add
several more index opclasses so that there is no regression in functionality
for base datatypes. initdb forced due to catalog additions.
target columns in INSERT and UPDATE targetlists. Don't rely on resname
to be accurate in ruleutils, either. This fixes bug reported by
Donald Fraser, in which renaming a column referenced in a rule did not
work very well.
'scalar op ALL (array)', where the operator is applied between the
lefthand scalar and each element of the array. The operator must
yield boolean; the result of the construct is the OR or AND of the
per-element results, respectively.
Original coding by Joe Conway, after an idea of Peter's. Rewritten
by Tom to keep the implementation strictly separate from subqueries.
of an index can now be a computed expression instead of a simple variable.
Restrictions on expressions are the same as for predicates (only immutable
functions, no sub-selects). This fixes problems recently introduced with
inlining SQL functions, because the inlining transformation is applied to
both expression trees so the planner can still match them up. Along the
way, improve efficiency of handling index predicates (both predicates and
index expressions are now cached by the relcache) and fix 7.3 oversight
that didn't record dependencies of predicate expressions.
rewritten and the protocol is changed, but most elog calls are still
elog calls. Also, we need to contemplate mechanisms for controlling
all this functionality --- eg, how much stuff should appear in the
postmaster log? And what API should libpq expose for it?
expressions, ARRAY(sub-SELECT) expressions, some array functions.
Polymorphic functions using ANYARRAY/ANYELEMENT argument and return
types. Some regression tests in place, documentation is lacking.
Joe Conway, with some kibitzing from Tom Lane.
CHECK constraints.
There are apparently no other types of constraint in pg_constraint, so
now all bases are covered. Also, this patch assumes that consrc for a
CHECK constraint is always bracketed so that it's not necessary to add
extra brackets.
Christopher Kings-Lynne
startup, not in the parser; this allows ALTER DOMAIN to work correctly
with domain constraint operations stored in rules. Rod Taylor;
code review by Tom Lane.
Simplify SubLink by storing just a List of operator OIDs, instead of
a list of incomplete OpExprs --- that was a bizarre and bulky choice,
with no redeeming social value since we have to build new OpExprs
anyway when forming the plan tree.
'NOT (x IN (subselect))', that is 'NOT (x = ANY (subselect))',
rather than 'x <> ALL (subselect)' as we formerly did. This
opens the door to optimizing NOT IN the same way as IN, whereas
there's no hope of optimizing the expression using <>. Also,
convert 'x <> ALL (subselect)' to the NOT(IN) style, so that
the optimization will be available when processing rules dumped
by older Postgres versions.
initdb forced due to small change in SubLink node representation.
> The big problem is that while pg_dump's dump_trigger() looks at
> tginitdeferred and dumps accordingly, pg_get_constraintdef doesn't look
> at tginitdeferred, and therefore doesn't record the requirement as part
> of ALTER TABLE ADD CONSTRAINT.
pg_get_constraintdef should probably be looking at condeferrable and
condeferred in the pg_constraint row it's looking at. Maybe something
like the attached.
(Added, output only non-default values.)
Stephan Szabo
in the planned representation of a subplan at all any more, only SubPlan.
This means subselect.c doesn't scribble on its input anymore, which seems
like a good thing; and there are no longer three different possible
interpretations of a SubLink. Simplify node naming and improve comments
in primnodes.h. No change to stored rules, though.
so that all executable expression nodes inherit from a common supertype
Expr. This is somewhat of an exercise in code purity rather than any
real functional advance, but getting rid of the extra Oper or Func node
formerly used in each operator or function call should provide at least
a little space and speed improvement.
initdb forced by changes in stored-rules representation.
sublink results and COPY's domain constraint checking. A Const that
isn't really constant is just a Bad Idea(tm). Remove hacks in
parse_coerce and other places that were needed because of the former
klugery.
composite types. Add a couple more lsyscache.c routines to support this,
and make use of them in some other places that were doing lookups the
hard way.
ruleutils display is not such a great idea. For arguments of functions
and operators I think we'd better keep the historical behavior of showing
such casts explicitly, to ensure that the function/operator is reparsed
the same way when the rule is reloaded. This also makes the output of
EXPLAIN less obscurantist about exactly what's happening.
to be flexible about assignment casts without introducing ambiguity in
operator/function resolution. Introduce a well-defined promotion hierarchy
for numeric datatypes (int2->int4->int8->numeric->float4->float8).
Change make_const to initially label numeric literals as int4, int8, or
numeric (never float8 anymore).
Explicitly mark Func and RelabelType nodes to indicate whether they came
from a function call, explicit cast, or implicit cast; use this to do
reverse-listing more accurately and without so many heuristics.
Explicit casts to char, varchar, bit, varbit will truncate or pad without
raising an error (the pre-7.2 behavior), while assigning to a column without
any explicit cast will still raise an error for wrong-length data like 7.3.
This more nearly follows the SQL spec than 7.2 behavior (we should be
reporting a 'completion condition' in the explicit-cast cases, but we have
no mechanism for that, so just do silent truncation).
Fix some problems with enforcement of typmod for array elements;
it didn't work at all in 'UPDATE ... SET array[n] = foo', for example.
Provide a generalized array_length_coerce() function to replace the
specialized per-array-type functions that used to be needed (and were
missing for NUMERIC as well as all the datetime types).
Add missing conversions int8<->float4, text<->numeric, oid<->int8.
initdb forced.
type for runtime constraint checks, instead of misusing the parse-time
Constraint node for the purpose. Fix some damage introduced into type
coercion logic; in particular ensure that a coerced expression tree will
read out the correct result type when inspected (patch had broken some
RelabelType cases). Enforce domain NOT NULL constraints against columns
that are omitted from an INSERT.
array header, and to compute sizing and alignment of array elements
the same way normal tuple access operations do --- viz, using the
tupmacs.h macros att_addlength and att_align. This makes the world
safe for arrays of cstrings or intervals, and should make it much
easier to write array-type-polymorphic functions; as examples see
the cleanups of array_out and contrib/array_iterator. By Joe Conway
and Tom Lane.
The -n and -N options were removed. Quoting is now smart enough to
supply quotes if and only if necessary.
Numerical types are now printed without quotes, except in cases of
special values such as NaN.
Boolean values printed as true and false.
Most string literals now do not escape whitespace characters (newlines,
etc.) for portability.
SET SESSION AUTHORIZATION argument is a string literal, to follow SQL.
Made commands output by pg_dump use consistent spacing and indentation.
sets of triggers. Also modify psql \d command to show foreign key
constraints as such and hide the triggers. pg_get_constraintdef()
function added to backend to support these. From Rod Taylor, code
review and some editorialization by Tom Lane.
