type coercion after failing to find an exact match in pg_proc, but before
considering interpretations that involve a function call with one or
more argument type coercions. This avoids surprises wherein what looks
like a type coercion is interpreted as coercing to some third type and
then to the destination type, as in Dave Blasby's bug report of 3-Oct-01.
See subsequent discussion in pghackers.
/*
* parse function
* This code is confusing because the database can accept
* relation.column, column.function, or relation.column.function.
* In these cases, funcname is the last parameter, and fargs are
* the rest.
*
* It can also be called as func(col) or func(col,col).
* In this case, Funcname is the part before parens, and fargs
* are the part in parens.
*
*/
Node *
ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
bool agg_star, bool agg_distinct,
int precedence)
functions of join or subselect aliases. It'd be awfully nice if this
code knew for sure whether it was dealing with 'x.f' or 'f(x)' syntax;
maybe we can fix that in a future cycle.
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.
attributes in a FieldSelect node --- all the places that manipulate
these work just fine with system attribute numbers. OK, it's a new
feature, so shoot me ...
1. Distinguish cases where a Datum representing a tuple datatype is an OID
from cases where it is a pointer to TupleTableSlot, and make sure we use
the right typlen in each case.
2. Make fetchatt() and related code support 8-byte by-value datatypes on
machines where Datum is 8 bytes. Centralize knowledge of the available
by-value datatype sizes in two macros in tupmacs.h, so that this will be
easier if we ever have to do it again.
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.
any available string type. Previously, all candidate choices must have
fallen within the same "type category" for PostgreSQL to be willing to
choose any of them.
Need to apply the same fixup to operator type resolution.
(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!
for example, an SQL function can be used in a functional index. (I make
no promises about speed, but it'll work ;-).) Clean up and simplify
handling of functions returning sets.
from Param nodes, per discussion a few days ago on pghackers. Add new
expression node type FieldSelect that implements the functionality where
it's actually needed. Clean up some other unused fields in Func nodes
as well.
NOTE: initdb forced due to change in stored expression trees for rules.
These two routines will now ALWAYS elog() on failure, whether you ask for
a lock or not. If you really want to get a NULL return on failure, call
the new routines heap_open_nofail()/heap_openr_nofail(). By my count there
are only about three places that actually want that behavior. There were
rather more than three places that were missing the check they needed to
make under the old convention :-(.
quote-stripping, and acl-checking tasks for these functions from the
parser, and do them at function execution time instead. This fixes
the failure of pg_dump to produce correct output for nextval(Foo)
used in a rule, and also eliminates the restriction that the argument
of these functions must be a parse-time constant.
key call sites are changed, but most called functions are still oldstyle.
An exception is that the PL managers are updated (so, for example, NULL
handling now behaves as expected in plperl and plpgsql functions).
NOTE initdb is forced due to added column in pg_proc.
In function parsing, try for an actual function of the given name and
input types before trying to interpret the function call as a type
coercion request, rather than after. Before, a function that had the
same name as a type and operated on a binary-compatible type wouldn't
get invoked. Also, cross-pollinate between func_select_candidates and
oper_select_candidates to ensure that they use as nearly the same
resolution rules as possible. A few other minor code cleanups too.
actually a type-coercion problem. If you have a function defined on
class A, and class B inherits from A, then the function ought to work
on class B as well --- but coerce_type didn't know that. Now it does.
Implement TIME WITH TIME ZONE type (timetz internal type).
Remap length() for character strings to CHAR_LENGTH() for SQL92
and to remove the ambiguity with geometric length() functions.
Keep length() for character strings for backward compatibility.
Shrink stored views by removing internal column name list from visible rte.
Implement min(), max() for time and timetz data types.
Implement conversion of TIME to INTERVAL.
Implement abs(), mod(), fac() for the int8 data type.
Rename some math functions to generic names:
round(), sqrt(), cbrt(), pow(), etc.
Rename NUMERIC power() function to pow().
Fix int2 factorial to calculate result in int4.
Enhance the Oracle compatibility function translate() to work with string
arguments (from Edwin Ramirez).
Modify pg_proc system table to remove OID holes.
coercion code. I'm beginning to wonder why we have separate candidate
selection routines for functions, operators, and aggregates --- shouldn't
this code all be unified? But meanwhile,
SELECT 'a' LIKE 'a';
finally works; the code for dealing with unknown input types for operators
was pretty busted.
as representing a type coercion request in more cases than we did before.
It will work now whenever no underlying function is required, ie if the
coercion is binary-compatible or if the argument is a previously untyped
string constant. Otherwise, you still need a real function to exist.
represent the result of a binary-compatible type coercion. At runtime
it just evaluates its argument --- but during type resolution, exprType
will pick up the output type of the RelabelType node instead of the type
of the argument. This solves some longstanding problems with dropped
type coercions, an example being 'select now()::abstime::int4' which
used to produce date-formatted output, not an integer, because the
coercion to int4 was dropped on the floor.
agg_select_candidate, which could cause them to keep more candidates
than they should and thus fail to select a single match. I had
previously fixed the identical bug in oper_select_candidate, but
didn't realize that the same error was repeated over here.
Also, repair func_select_candidate's curious notion that it could
scribble on the input type-OID vector. That was causing failure to
apply necessary type coercion later on, leading to malfunction of
examples such as select date('now').
SELECT a FROM t1 tx (a);
Allow join syntax, including queries like
SELECT * FROM t1 NATURAL JOIN t2;
Update RTE structure to hold column aliases in an Attr structure.
yet, but at least we can give a better error message:
regression=> select count(distinct f1) from int4_tbl;
ERROR: aggregate(DISTINCT ...) is not implemented yet
instead of 'parser: parse error at or near distinct'.
(which are palloc'd) instead of DLLists (which are malloc'd). Not very
significant, since this routine seldom has anything useful to do, but
a leak is a leak...
Make all system indexes unique.
Make all cache loads use system indexes.
Rename *rel to *relid in inheritance tables.
Rename cache names to be clearer.
Tom Lane
Peter Eisentraut
Jan Wieck
Bruce Momjian
Thomas G. Lockhart