of the containing query (which really can only happen in a rule context).
Per example from Brandon Craig Rhodes. Also, make the error message
more specific for the similar case with sub-select in FROM. The revised
coding should be easier to adapt to SQL99's LATERAL(), when we get around
to supporting that.
> =================================================================
> User interface proposal for multi-row function targetlist entries
> =================================================================
> 1. Only one targetlist entry may return a set.
> 2. Each targetlist item (other than the set returning one) is
> repeated for each item in the returned set.
>
Having gotten no objections (actually, no response at all), I can only
assume no one had heartburn with this change. The attached patch covers
the first of the two proposals, i.e. restricting the target list to only
one set returning function.
Joe Conway
> User interface proposal for multi-row function targetlist entries
> =================================================================
> 1. Only one targetlist entry may return a set.
> 2. Each targetlist item (other than the set returning one) is
> repeated for each item in the returned set.
>
Having gotten no objections (actually, no response at all), I can only assume
no one had heartburn with this change. The attached patch covers the first of
the two proposals, i.e. restricting the target list to only one set returning
function.
It compiles cleanly, and passes all regression tests. If there are no
objections, please apply.
Any suggestions on where this should be documented (other than maybe sql-select)?
Thanks,
Joe
p.s. Here's what the previous example now looks like:
CREATE TABLE bar(f1 int, f2 text, f3 int);
INSERT INTO bar VALUES(1, 'Hello', 42);
INSERT INTO bar VALUES(2, 'Happy', 45);
CREATE TABLE foo(a int, b text);
INSERT INTO foo VALUES(42, 'World');
INSERT INTO foo VALUES(42, 'Everyone');
INSERT INTO foo VALUES(45, 'Birthday');
INSERT INTO foo VALUES(45, 'New Year');
CREATE TABLE foo2(a int, b text);
INSERT INTO foo2 VALUES(42, '!!!!');
INSERT INTO foo2 VALUES(42, '????');
INSERT INTO foo2 VALUES(42, '####');
INSERT INTO foo2 VALUES(45, '$$$$');
CREATE OR REPLACE FUNCTION getfoo(int) RETURNS SETOF text AS '
SELECT b FROM foo WHERE a = $1
' language 'sql';
CREATE OR REPLACE FUNCTION getfoo2(int) RETURNS SETOF text AS '
SELECT b FROM foo2 WHERE a = $1
' language 'sql';
regression=# SELECT f1, f2, getfoo(f3) AS f4 FROM bar;
f1 | f2 | f4
----+-------+----------
1 | Hello | World
1 | Hello | Everyone
2 | Happy | Birthday
2 | Happy | New Year
(4 rows)
regression=# SELECT f1, f2, getfoo(f3) AS f4, getfoo2(f3) AS f5 FROM bar;
ERROR: Only one target list entry may return a set result
Joe Conway
codes, per discussion from last March. parse.h should now be included
*only* by gram.y, scan.l, keywords.c, parser.c. This prevents surprising
misbehavior after seemingly-trivial grammar adjustments.
rid of the assumption that sizeof(Oid)==sizeof(int). This is one small
step towards someday supporting 8-byte OIDs. For the moment, it doesn't
do much except get rid of a lot of unsightly casts.
disallowed by CREATE TABLE (eg, pseudo-types); also disallow these types
from being introduced by the range-function syntax. While at it, allow
CREATE TABLE to create zero-column tables, per recent pghackers discussion.
I am back-patching this into 7.3 since failure to disallow pseudo-types
is arguably a security hole.
make VALUE a non-reserved word again, use less invasive method of passing
ConstraintTestValue into transformExpr, fix problems with nested constraint
testing, do correct thing with NULL result from a constraint expression,
remove memory leak. Domain checks still need much more work if we are going
to allow ALTER DOMAIN, however.
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.
operations: make sure we use operators that are compatible, as determined
by a mergejoin link in pg_operator. Also, add code to planner to ensure
we don't try to use hashed grouping when the grouping operators aren't
marked hashable.
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.
when two equal() targetlist items were to be added to an ORDER BY or
DISTINCT list. Although indeed this would make sorting fractionally
faster by sometimes saving a comparison, it confuses the heck out of
later stages of processing, because it makes it look like the user
wrote DISTINCT ON rather than DISTINCT. Bug reported by joe@piscitella.com.
types for Table Functions, as previously proposed on HACKERS. Here is a
brief explanation:
1. Creates a new pg_type typtype: 'p' for pseudo type (currently either
'b' for base or 'c' for catalog, i.e. a class).
2. Creates new builtin type of typtype='p' named RECORD. This is the
first of potentially several pseudo types.
3. Modify FROM clause grammer to accept:
SELECT * FROM my_func() AS m(colname1 type1, colname2 type1, ...)
where m is the table alias, colname1, etc are the column names, and
type1, etc are the column types.
4. When typtype == 'p' and the function return type is RECORD, a list
of column defs is required, and when typtype != 'p', it is
disallowed.
5. A check was added to ensure that the tupdesc provide via the parser
and the actual return tupdesc match in number and type of
attributes.
When creating a function you can do:
CREATE FUNCTION foo(text) RETURNS setof RECORD ...
When using it you can do:
SELECT * from foo(sqlstmt) AS (f1 int, f2 text, f3 timestamp)
or
SELECT * from foo(sqlstmt) AS f(f1 int, f2 text, f3 timestamp)
or
SELECT * from foo(sqlstmt) f(f1 int, f2 text, f3 timestamp)
Included in the patches are adjustments to the regression test sql and
expected files, and documentation.
p.s.
This potentially solves (or at least improves) the issue of builtin
Table Functions. They can be bootstrapped as returning RECORD, and
we can wrap system views around them with properly specified column
defs. For example:
CREATE VIEW pg_settings AS
SELECT s.name, s.setting
FROM show_all_settings()AS s(name text, setting text);
Then we can also add the UPDATE RULE that I previously posted to
pg_settings, and have pg_settings act like a virtual table, allowing
settings to be queried and set.
Joe Conway
process function RTE expressions, which they were previously missing.
This allows outer-Var references and subselects to work correctly in
the arguments of a function RTE. Install check to prevent function RTEs
from cross-referencing Vars of sibling FROM-items, which doesn't make
any sense (if you want to join, write a JOIN or WHERE clause).
returns-set boolean field in Func and Oper nodes. This allows cleaner,
more reliable tests for expressions returning sets in the planner and
parser. For example, a WHERE clause returning a set is now detected
and complained of in the parser, not only at runtime.
some kibitzing from Tom Lane. Not everything works yet, and there's
no documentation or regression test, but let's commit this so Joe
doesn't need to cope with tracking changes in so many files ...
lists to join RTEs, attach a list of Vars and COALESCE expressions that will
replace the join's alias variables during planning. This simplifies
flatten_join_alias_vars while still making it easy to fix up varno references
when transforming the query tree. Add regression test cases for interactions
of subqueries with outer joins.
qualified operator names directly, for example CREATE OPERATOR myschema.+
( ... ). To qualify an operator name in an expression you need to write
OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch).
I also took advantage of having to reformat pg_operator to fix something
that'd been bugging me for a while: mergejoinable operators should have
explicit links to the associated cross-data-type comparison operators,
rather than hardwiring an assumption that they are named < and >.
in schemas other than the system namespace; however, there's no search
path yet, and not all operations work yet on tables outside the system
namespace.
addRangeTableEntry calls. Remove relname field from RTEs, since
it will no longer be a useful unique identifier of relations;
we want to encourage people to rely on the relation OID instead.
Further work on dumping qual expressions in EXPLAIN, too.
the parsetree representation. As yet we don't *do* anything with schema
names, just drop 'em on the floor; but you can enter schema-compatible
command syntax, and there's even a primitive CREATE SCHEMA command.
No doc updates yet, except to note that you can now extract a field
from a function-returning-row's result with (foo(...)).fieldname.
now has an RTE of its own, and references to its outputs now are Vars
referencing the JOIN RTE, rather than CASE-expressions. This allows
reverse-listing in ruleutils.c to use the correct alias easily, rather
than painfully reverse-engineering the alias namespace as it used to do.
Also, nested FULL JOINs work correctly, because the result of the inner
joins are simple Vars that the planner can cope with. This fixes a bug
reported a couple times now, notably by Tatsuo on 18-Nov-01. The alias
Vars are expanded into COALESCE expressions where needed at the very end
of planning, rather than during parsing.
Also, beginnings of support for showing plan qualifier expressions in
EXPLAIN. There are probably still cases that need work.
initdb forced due to change of stored-rule representation.
tests to return the correct results per SQL9x when given NULL inputs.
Reimplement these tests as well as IS [NOT] NULL to have their own
expression node types, instead of depending on special functions.
From Joe Conway, with a little help from Tom Lane.
1. If there is exactly one pg_operator entry of the right name and oprkind,
oper() and related routines would return that entry whether its input type
had anything to do with the request or not. This is just premature
optimization: we shouldn't return the single candidate until after we verify
that it really is a valid candidate, ie, is at least coercion-compatible
with the given types.
2. oper() and related routines only promise a coercion-compatible result.
Unfortunately, there were quite a few callers that assumed the returned
operator is binary-compatible with the given datatype; they would proceed
to call it without making any datatype coercions. These callers include
sorting, grouping, aggregation, and VACUUM ANALYZE. In general I think
it is appropriate for these callers to require an exact or binary-compatible
match, so I've added a new routine compatible_oper() that only succeeds if
it can find an operator that doesn't require any run-time conversions.
Callers now call oper() or compatible_oper() depending on whether they are
prepared to deal with type conversion or not.
The upshot of these bugs is revealed by the following silliness in PL/Tcl's
selftest: it creates an operator @< on int4, and then tries to use it to
sort a char(N) column. The system would let it do that :-( (and evidently
has done so since 6.3 :-( :-(). The result in this case was just a silly
sort order, but the reverse combination would've provoked coredump from
trying to dereference integers. With this fix you get more reasonable
behavior:
pltcl_test=# select * from T_pkey1 order by key1, key2 using @<;
ERROR: Unable to identify an operator '@<' for types 'bpchar' and 'bpchar'
You will have to retype this query using an explicit cast
clause with an alias is a <subquery> and therefore hides table references
appearing within it, according to the spec. This is the same as the
preliminary patch I posted to pgsql-patches yesterday, plus some really
grotty code in ruleutils.c to reverse-list a query tree with the correct
alias name depending on context. I'd rather not have done that, but unless
we want to force another initdb for 7.1, there's no other way for now.
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.
maintained for each cache entry. A cache entry will not be freed until
the matching ReleaseSysCache call has been executed. This eliminates
worries about cache entries getting dropped while still in use. See
my posting to pg-hackers of even date for more info.
joins, and clean things up a good deal at the same time. Append plan node
no longer hacks on rangetable at runtime --- instead, all child tables are
given their own RT entries during planning. Concept of multiple target
tables pushed up into execMain, replacing bug-prone implementation within
nodeAppend. Planner now supports generating Append plans for inheritance
sets either at the top of the plan (the old way) or at the bottom. Expanding
at the bottom is appropriate for tables used as sources, since they may
appear inside an outer join; but we must still expand at the top when the
target of an UPDATE or DELETE is an inheritance set, because we actually need
a different targetlist and junkfilter for each target table in that case.
Fortunately a target table can't be inside an outer join... Bizarre mutual
recursion between union_planner and prepunion.c is gone --- in fact,
union_planner doesn't really have much to do with union queries anymore,
so I renamed it grouping_planner.
(WAL logging for this is not done yet, however.) Clean up a number of really
crufty things that are no longer needed now that DROP behaves nicely. Make
temp table mapper do the right things when drop or rename affecting a temp
table is rolled back. Also, remove "relation modified while in use" error
check, in favor of locking tables at first reference and holding that lock
throughout the statement.
took some rejiggering of typename and ACL parsing, as well as moving
parse_analyze call out of parser(). Restructure postgres.c processing
so that parse analysis and rewrite are skipped when in abort-transaction
state. Only COMMIT and ABORT statements will be processed beyond the raw
parser() phase. This addresses problem of parser failing with database access
errors while in aborted state (see pghackers discussions around 7/28/00).
Also fix some bugs with COMMIT/ABORT statements appearing in the middle of
a single query input string.
Function, operator, and aggregate arguments/results can now use full
TypeName production, in particular foo[] for array types.
DROP OPERATOR and COMMENT ON OPERATOR were broken for unary operators.
Allow CREATE AGGREGATE to accept unquoted numeric constants for initcond.
SQL92 semantics, including support for ALL option. All three can be used
in subqueries and views. DISTINCT and ORDER BY work now in views, too.
This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT
where the SELECT yields different datatypes than the INSERT needs. I did
that by making UNION subqueries and SELECT in INSERT be treated like
subselects-in-FROM, thereby allowing an extra level of targetlist where the
datatype conversions can be inserted safely.
INITDB NEEDED!
(Don't forget that an alias is required.) Views reimplemented as expanding
to subselect-in-FROM. Grouping, aggregates, DISTINCT in views actually
work now (he says optimistically). No UNION support in subselects/views
yet, but I have some ideas about that. Rule-related permissions checking
moved out of rewriter and into executor.
INITDB REQUIRED!
ie, consider only the columns coming from the JOIN clause's sub-clauses.
Also detect attempts to reference columns belonging to other tables
(which would still be possible using an explicitly-qualified name).
I'm not sure this implements the spec's semantics 100% accurately, but
at least it gives plausible behavior.
