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apache / hawq / bd6196f487c8028f3eca0f56509fe9d718ee31c6 / . / src / backend / parser / parse_func.c
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/*-------------------------------------------------------------------------
*
* parse_func.c
* handle function calls in parser
*
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.190 2006/10/04 00:29:55 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "catalog/catquery.h"
#include "access/transam.h"
#include "catalog/pg_aggregate.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_proc_callback.h"
#include "catalog/pg_type.h"
#include "catalog/pg_window.h"
#include "funcapi.h"
#include "nodes/makefuncs.h"
#include "optimizer/walkers.h"
#include "parser/parse_agg.h"
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "parser/parse_func.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
static Node *ParseComplexProjection(ParseState *pstate, char *funcname,
Node *first_arg, int location);
static void unknown_attribute(ParseState *pstate, Node *relref, char *attname,
int location);
typedef struct
{
Node *parent;
} check_table_func_context;
static bool
checkTableFunctions_walker(Node *node, check_table_func_context *context);
/*
* Parse a function call
*
* For historical reasons, Postgres tries to treat the notations tab.col
* and col(tab) as equivalent: if a single-argument function call has an
* argument of complex type and the (unqualified) function name matches
* any attribute of the type, we take it as a column projection. Conversely
* a function of a single complex-type argument can be written like a
* column reference, allowing functions to act like computed columns.
*
* Hence, both cases come through here. The is_column parameter tells us
* which syntactic construct is actually being dealt with, but this is
* intended to be used only to deliver an appropriate error message,
* not to affect the semantics. When is_column is true, we should have
* a single argument (the putative table), unqualified function name
* equal to the column name, and no aggregate decoration.
*
* The argument expressions (in fargs) must have been transformed already.
*/
Node *
ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
List *agg_order, bool agg_star, bool agg_distinct,
bool is_column, WindowSpec *over, int location,
Node *agg_filter)
{
Oid rettype = InvalidOid;
Oid funcid = InvalidOid;
ListCell *l;
ListCell *nextl;
Node *first_arg = NULL;
int nargs;
Oid actual_arg_types[FUNC_MAX_ARGS];
Oid *declared_arg_types = NULL;
Node *retval = NULL;
bool retset = false;
bool retstrict = false;
bool retordered = false;
FuncDetailCode fdresult;
/*
* Most of the rest of the parser just assumes that functions do not have
* more than FUNC_MAX_ARGS parameters. We have to test here to protect
* against array overruns, etc. Of course, this may not be a function,
* but the test doesn't hurt.
*/
if (list_length(fargs) > FUNC_MAX_ARGS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
errmsg("cannot pass more than %d arguments to a function",
FUNC_MAX_ARGS),
parser_errposition(pstate, location)));
/*
* Perform the FILTER -> CASE transform.
* FUNC(expr) FILTER (WHERE cond) => FUNC(CASE WHEN cond THEN expr END)
* This must be done for every parameter of the function and special handling
* is needed for FUNC(*).
*
* For this to be a valid transform we must assume that NULLs passed into
* the function will not change the result. This assumption is not valid
* for count(*), which is why we need special processing for this case. If
* it is not a valid assumption for other cases we may need to rethink how
* we implement FILTER.
*/
if (agg_filter)
{
List *newfargs = NULL;
if (agg_star || !fargs)
{
/*
* FUNC(*) => assume that datatype doesn't matter
* By converting agg_star into a conditional constant boolean
* expression we get the correct results for count(*) since it
* will then supress the NULLs returned by the CASE statement.
*/
CaseExpr *c = makeNode(CaseExpr);
CaseWhen *w = makeNode(CaseWhen);
A_Const *a = makeNode(A_Const);
a->val.type = T_Integer;
a->val.val.ival = 1; /* Actual value shouldn't matter */
w->expr = (Expr *) agg_filter;
w->result = (Expr *) a;
c->casetype = InvalidOid; /* will analyze in a moment */
c->arg = (Expr *) NULL;
c->defresult = (Expr *) NULL;
c->args = list_make1(w);
newfargs = list_make1(c);
/*
* Since we haven't checked the compatability of our function with
* agg_star we can not clear the local bit yet, otherwise we would
* loose track of the fact that this was an agg_star operation prior
* to transformation.
*/
}
else
{
Assert(fargs && list_length(fargs) > 0);
foreach(l, fargs)
{
CaseExpr *c = makeNode(CaseExpr);
CaseWhen *w = makeNode(CaseWhen);
w->expr = (Expr *) agg_filter;
w->result = (Expr *) lfirst(l);
c->casetype = InvalidOid; /* will analyze in a moment */
c->arg = (Expr *) NULL;
c->defresult = (Expr *) NULL;
c->args = list_make1(w);
if (newfargs)
lappend(newfargs, c);
else
newfargs = list_make1(c);
}
}
fargs = transformExpressionList(pstate, newfargs);
}
/*
* Extract arg type info in preparation for function lookup.
*
* If any arguments are Param markers of type VOID, we discard them from
* the parameter list. This is a hack to allow the JDBC driver to not
* have to distinguish "input" and "output" parameter symbols while
* parsing function-call constructs. We can't use foreach() because we
* may modify the list ...
*/
nargs = 0;
for (l = list_head(fargs); l != NULL; l = nextl)
{
Node *arg = lfirst(l);
Oid argtype = exprType(arg);
nextl = lnext(l);
if (argtype == VOIDOID && IsA(arg, Param) &&!is_column)
{
fargs = list_delete_ptr(fargs, arg);
continue;
}
actual_arg_types[nargs++] = argtype;
}
if (fargs)
{
first_arg = linitial(fargs);
Assert(first_arg != NULL);
}
/*
* Check for column projection: if function has one argument, and that
* argument is of complex type, and function name is not qualified, then
* the "function call" could be a projection. We also check that there
* wasn't any aggregate decoration.
*/
if (nargs == 1 && agg_order == NIL && !agg_star && !agg_distinct &&
!agg_filter && list_length(funcname) == 1)
{
Oid argtype = actual_arg_types[0];
if (argtype == RECORDOID || ISCOMPLEX(argtype))
{
retval = ParseComplexProjection(pstate,
strVal(linitial(funcname)),
first_arg,
location);
if (retval)
return retval;
/*
* If ParseComplexProjection doesn't recognize it as a projection,
* just press on.
*/
}
}
/*
* Okay, it's not a column projection, so it must really be a function.
* func_get_detail looks up the function in the catalogs, does
* disambiguation for polymorphic functions, handles inheritance, and
* returns the funcid and type and set or singleton status of the
* function's return value. it also returns the true argument types to
* the function.
*/
fdresult = func_get_detail(funcname, fargs, nargs, actual_arg_types,
&funcid, &rettype, &retset, &retstrict,
&retordered, &declared_arg_types);
if (fdresult == FUNCDETAIL_COERCION)
{
/*
* We can do it as a trivial coercion. coerce_type can handle these
* cases, so why duplicate code...
*/
return coerce_type(pstate, linitial(fargs),
actual_arg_types[0], rettype, -1,
COERCION_EXPLICIT, COERCE_EXPLICIT_CALL,
-1);
}
else if (fdresult == FUNCDETAIL_NORMAL)
{
/*
* Normal function found; was there anything indicating it must be an
* aggregate?
*/
if (agg_star)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("%s(*) specified, but %s is not an aggregate function",
NameListToString(funcname),
NameListToString(funcname)),
parser_errposition(pstate, location)));
if (agg_distinct)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("DISTINCT specified, but %s is not an aggregate function",
NameListToString(funcname)),
errOmitLocation(true),
parser_errposition(pstate, location)));
if (agg_order)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("ORDER BY specified, but %s is not an ordered aggregate function",
NameListToString(funcname)),
errOmitLocation(true),
parser_errposition(pstate, location)));
if (agg_filter)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("filter clause specified, but "
"%s is not an aggregate function",
NameListToString(funcname)),
errOmitLocation(true),
parser_errposition(pstate, location)));
}
else if (fdresult != FUNCDETAIL_AGGREGATE)
{
/*
* Oops. Time to die.
*
* If we are dealing with the attribute notation rel.function, give an
* error message that is appropriate for that case.
*/
if (is_column)
{
Assert(nargs == 1);
Assert(list_length(funcname) == 1);
unknown_attribute(pstate, first_arg, strVal(linitial(funcname)),
location);
}
/*
* Else generate a detailed complaint for a function
*/
if (fdresult == FUNCDETAIL_MULTIPLE)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_FUNCTION),
errmsg("function %s is not unique",
func_signature_string(funcname, nargs,
actual_arg_types)),
errhint("Could not choose a best candidate function. "
"You may need to add explicit type casts."),
errOmitLocation(true),
parser_errposition(pstate, location)));
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("function %s does not exist",
func_signature_string(funcname, nargs,
actual_arg_types)),
errhint("No function matches the given name and argument types. "
"You may need to add explicit type casts."),
errOmitLocation(true),
parser_errposition(pstate, location)));
}
/*
* The agg_filter rewrite in the case of agg_star is only valid for count(*)
* otherwise we need to throw an error.
*/
if (agg_star && agg_filter && funcid != COUNT_ANY_OID)
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("function %s() does not exist",
NameListToString(funcname)),
errhint("No function matches the given name and argument types. "
"You may need to add explicit type casts."),
errOmitLocation(true),
parser_errposition(pstate, location)));
}
/*
* enforce consistency with ANYARRAY and ANYELEMENT argument and return
* types, possibly adjusting return type or declared_arg_types (which will
* be used as the cast destination by make_fn_arguments)
*/
rettype = enforce_generic_type_consistency(actual_arg_types,
declared_arg_types,
nargs,
rettype);
/* perform the necessary typecasting of arguments */
make_fn_arguments(pstate, fargs, actual_arg_types, declared_arg_types);
/* build the appropriate output structure */
if (fdresult == FUNCDETAIL_NORMAL && over == NULL)
{
FuncExpr *funcexpr = makeNode(FuncExpr);
funcexpr->funcid = funcid;
funcexpr->funcresulttype = rettype;
funcexpr->funcretset = retset;
funcexpr->funcformat = COERCE_EXPLICIT_CALL;
funcexpr->args = fargs;
retval = (Node *) funcexpr;
}
else if(over != NULL)
{
/* must be a window function call */
WindowRef *winref = makeNode(WindowRef);
HeapTuple tuple;
cqContext *wincqCtx;
if (retset)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("window functions may not return sets"),
parser_errposition(pstate, location)));
if (agg_order)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("aggregate ORDER BY is not implemented for window functions"),
parser_errposition(pstate, location)));
/*
* If this is a "true" window function, rather than an aggregate
* derived window function then it will have a tuple in pg_window
*/
wincqCtx = caql_beginscan(
NULL,
cql("SELECT * FROM pg_window "
" WHERE winfnoid = :1 ",
ObjectIdGetDatum(funcid)));
tuple = caql_getnext(wincqCtx);
if (HeapTupleIsValid(tuple))
{
if (agg_filter)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("window function \"%s\" can not be used with a "
"filter clause",
NameListToString(funcname)),
parser_errposition(pstate, location)));
/*
* We perform more checks – such as whether the window
* function requires ordering or permits a frame specification –
* later in transformWindowClause(). It's too early at this stage.
*/
}
caql_endscan(wincqCtx);
winref->winfnoid = funcid;
winref->restype = rettype;
winref->args = fargs;
{
/*
* Find if this "over" clause has already existed. If so,
* We let the "winspec" for this WindowRef point to
* the existing "over" clause. In this way, we will be able
* to determine if two WindowRef nodes are actually equal,
* see MPP-4268.
*/
int winspec = 0;
ListCell *over_lc = NULL;
transformWindowSpec(pstate, over);
foreach (over_lc, pstate->p_win_clauses)
{
Node *over1 = lfirst(over_lc);
if (equal(over1, over))
break;
winspec++;
}
if (over_lc == NULL)
pstate->p_win_clauses = lappend(pstate->p_win_clauses, over);
winref->winspec = winspec;
}
winref->windistinct = agg_distinct;
winref->location = location;
transformWindowFuncCall(pstate, winref);
retval = (Node *) winref;
}
else
{
/* aggregate function */
Aggref *aggref;
/*
* Reject attempt to call a parameterless aggregate without (*)
* syntax. This is mere pedantry but some folks insisted ...
*/
if (fargs == NIL && !agg_star)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("%s(*) must be used to call a parameterless aggregate function",
NameListToString(funcname)),
parser_errposition(pstate, location)));
/*
* We only support FILTER clauses over STRICT aggegation functions.
*
* All built in aggregations are strict except for int2_sum,
* int4_sum, and int8_sum, all of which are logically strict, but are
* simply defined as non-strict to bootstrap their calculations.
* Since they are logically strict we will not change their results
* by including extra nulls in the calculation so the rewrite won't
* produce incorrect results.
*
* For user defined functions we must enforce this restriction since
* passing "extra" nulls back to a non-strict function may cause it
* to return an incorrect answer, eg: count_null(i) filter (...)
* wouldn't differeniate between data nulls vs filtered values.
*/
if (agg_filter && !retstrict &&
(funcid < SUM_OID_MIN || funcid > SUM_OID_MAX))
{
ereport(ERROR,
(errcode(ERRCODE_GP_FEATURE_NOT_SUPPORTED),
errmsg("function %s is not defined as STRICT",
func_signature_string(funcname, nargs,
actual_arg_types)),
errhint("The filter clause is only supported over functions "
"defined as STRICT."),
errOmitLocation(true)));
}
if (retset)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregates may not return sets"),
parser_errposition(pstate, location),
errOmitLocation(true)));
/*
* If this is not an ordered aggregate, but it was called with an
* aggregate order by specification then we must raise an error.
*/
if (!retordered && agg_order != NIL)
{
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("ORDER BY specified, but %s is not an ordered aggregate function",
NameListToString(funcname)),
errOmitLocation(true),
parser_errposition(pstate, location)));
}
/*
* ordered aggregates are not compatible with distinct
*/
if (agg_distinct && agg_order != NIL)
{
ereport(ERROR,
(errcode(ERRCODE_GP_FEATURE_NOT_SUPPORTED),
errmsg("ORDER BY and DISTINCT are mutually exclusive"),
errOmitLocation(true),
parser_errposition(pstate, location)));
}
/*
* Build the aggregate node and transform it
*
* Note: aggorder is handled inside transformAggregateCall()
*/
aggref = makeNode(Aggref);
aggref->aggfnoid = funcid;
aggref->aggtype = rettype;
aggref->args = fargs;
aggref->aggstar = agg_star;
aggref->aggdistinct = agg_distinct;
transformAggregateCall(pstate, aggref, agg_order);
retval = (Node *) aggref;
}
/*
* Mark the context if this is a dynamic typed function, if so we mustn't
* allow views to be created from this statement because we cannot
* guarantee that the future return type will be the same as the current
* return type.
*/
if (TypeSupportsDescribe(rettype))
{
Oid DescribeFuncOid = lookupProcCallback(funcid, PROMETHOD_DESCRIBE);
if (OidIsValid(DescribeFuncOid))
{
ParseState *state = pstate;
for (state = pstate; state; state = state->parentParseState)
state->p_hasDynamicFunction = true;
}
}
return retval;
}
/* func_match_argtypes()
*
* Given a list of candidate functions (having the right name and number
* of arguments) and an array of input datatype OIDs, produce a shortlist of
* those candidates that actually accept the input datatypes (either exactly
* or by coercion), and return the number of such candidates.
*
* Note that can_coerce_type will assume that UNKNOWN inputs are coercible to
* anything, so candidates will not be eliminated on that basis.
*
* NB: okay to modify input list structure, as long as we find at least
* one match. If no match at all, the list must remain unmodified.
*/
int
func_match_argtypes(int nargs,
Oid *input_typeids,
FuncCandidateList raw_candidates,
FuncCandidateList *candidates) /* return value */
{
FuncCandidateList current_candidate;
FuncCandidateList next_candidate;
int ncandidates = 0;
*candidates = NULL;
for (current_candidate = raw_candidates;
current_candidate != NULL;
current_candidate = next_candidate)
{
next_candidate = current_candidate->next;
if (can_coerce_type(nargs, input_typeids, current_candidate->args,
COERCION_IMPLICIT))
{
current_candidate->next = *candidates;
*candidates = current_candidate;
ncandidates++;
}
}
return ncandidates;
} /* func_match_argtypes() */
/* func_select_candidate()
* Given the input argtype array and more than one candidate
* for the function, attempt to resolve the conflict.
*
* Returns the selected candidate if the conflict can be resolved,
* otherwise returns NULL.
*
* Note that the caller has already determined that there is no candidate
* exactly matching the input argtypes, and has pruned away any "candidates"
* that aren't actually coercion-compatible with the input types.
*
* This is also used for resolving ambiguous operator references. Formerly
* parse_oper.c had its own, essentially duplicate code for the purpose.
* The following comments (formerly in parse_oper.c) are kept to record some
* of the history of these heuristics.
*
* OLD COMMENTS:
*
* This routine is new code, replacing binary_oper_select_candidate()
* which dates from v4.2/v1.0.x days. It tries very hard to match up
* operators with types, including allowing type coercions if necessary.
* The important thing is that the code do as much as possible,
* while _never_ doing the wrong thing, where "the wrong thing" would
* be returning an operator when other better choices are available,
* or returning an operator which is a non-intuitive possibility.
* - thomas 1998-05-21
*
* The comments below came from binary_oper_select_candidate(), and
* illustrate the issues and choices which are possible:
* - thomas 1998-05-20
*
* current wisdom holds that the default operator should be one in which
* both operands have the same type (there will only be one such
* operator)
*
* 7.27.93 - I have decided not to do this; it's too hard to justify, and
* it's easy enough to typecast explicitly - avi
* [the rest of this routine was commented out since then - ay]
*
* 6/23/95 - I don't complete agree with avi. In particular, casting
* floats is a pain for users. Whatever the rationale behind not doing
* this is, I need the following special case to work.
*
* In the WHERE clause of a query, if a float is specified without
* quotes, we treat it as float8. I added the float48* operators so
* that we can operate on float4 and float8. But now we have more than
* one matching operator if the right arg is unknown (eg. float
* specified with quotes). This break some stuff in the regression
* test where there are floats in quotes not properly casted. Below is
* the solution. In addition to requiring the operator operates on the
* same type for both operands [as in the code Avi originally
* commented out], we also require that the operators be equivalent in
* some sense. (see equivalentOpersAfterPromotion for details.)
* - ay 6/95
*/
FuncCandidateList
func_select_candidate(int nargs,
Oid *input_typeids,
FuncCandidateList candidates)
{
FuncCandidateList current_candidate;
FuncCandidateList last_candidate;
Oid *current_typeids;
Oid current_type;
int i;
int ncandidates;
int nbestMatch,
nmatch;
Oid input_base_typeids[FUNC_MAX_ARGS];
CATEGORY slot_category[FUNC_MAX_ARGS],
current_category;
bool slot_has_preferred_type[FUNC_MAX_ARGS];
bool resolved_unknowns;
/* protect local fixed-size arrays */
if (nargs > FUNC_MAX_ARGS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
errmsg("cannot pass more than %d arguments to a function",
FUNC_MAX_ARGS)));
/*
* If any input types are domains, reduce them to their base types. This
* ensures that we will consider functions on the base type to be "exact
* matches" in the exact-match heuristic; it also makes it possible to do
* something useful with the type-category heuristics. Note that this
* makes it difficult, but not impossible, to use functions declared to
* take a domain as an input datatype. Such a function will be selected
* over the base-type function only if it is an exact match at all
* argument positions, and so was already chosen by our caller.
*/
for (i = 0; i < nargs; i++)
input_base_typeids[i] = getBaseType(input_typeids[i]);
/*
* Run through all candidates and keep those with the most matches on
* exact types. Keep all candidates if none match.
*/
ncandidates = 0;
nbestMatch = 0;
last_candidate = NULL;
for (current_candidate = candidates;
current_candidate != NULL;
current_candidate = current_candidate->next)
{
current_typeids = current_candidate->args;
nmatch = 0;
for (i = 0; i < nargs; i++)
{
if (input_base_typeids[i] != UNKNOWNOID &&
current_typeids[i] == input_base_typeids[i])
nmatch++;
}
/* take this one as the best choice so far? */
if ((nmatch > nbestMatch) || (last_candidate == NULL))
{
nbestMatch = nmatch;
candidates = current_candidate;
last_candidate = current_candidate;
ncandidates = 1;
}
/* no worse than the last choice, so keep this one too? */
else if (nmatch == nbestMatch)
{
last_candidate->next = current_candidate;
last_candidate = current_candidate;
ncandidates++;
}
/* otherwise, don't bother keeping this one... */
}
if (last_candidate) /* terminate rebuilt list */
last_candidate->next = NULL;
if (ncandidates == 1)
return candidates;
/*
* Still too many candidates? Now look for candidates which have either
* exact matches or preferred types at the args that will require
* coercion. (Restriction added in 7.4: preferred type must be of same
* category as input type; give no preference to cross-category
* conversions to preferred types.) Keep all candidates if none match.
*/
for (i = 0; i < nargs; i++) /* avoid multiple lookups */
slot_category[i] = TypeCategory(input_base_typeids[i]);
ncandidates = 0;
nbestMatch = 0;
last_candidate = NULL;
for (current_candidate = candidates;
current_candidate != NULL;
current_candidate = current_candidate->next)
{
current_typeids = current_candidate->args;
nmatch = 0;
for (i = 0; i < nargs; i++)
{
if (input_base_typeids[i] != UNKNOWNOID)
{
if (current_typeids[i] == input_base_typeids[i] ||
IsPreferredType(slot_category[i], current_typeids[i]))
nmatch++;
}
}
if ((nmatch > nbestMatch) || (last_candidate == NULL))
{
nbestMatch = nmatch;
candidates = current_candidate;
last_candidate = current_candidate;
ncandidates = 1;
}
else if (nmatch == nbestMatch)
{
last_candidate->next = current_candidate;
last_candidate = current_candidate;
ncandidates++;
}
}
if (last_candidate) /* terminate rebuilt list */
last_candidate->next = NULL;
if (ncandidates == 1)
return candidates;
/*
* Still too many candidates? Try assigning types for the unknown columns.
*
* NOTE: for a binary operator with one unknown and one non-unknown input,
* we already tried the heuristic of looking for a candidate with the
* known input type on both sides (see binary_oper_exact()). That's
* essentially a special case of the general algorithm we try next.
*
* We do this by examining each unknown argument position to see if we can
* determine a "type category" for it. If any candidate has an input
* datatype of STRING category, use STRING category (this bias towards
* STRING is appropriate since unknown-type literals look like strings).
* Otherwise, if all the candidates agree on the type category of this
* argument position, use that category. Otherwise, fail because we
* cannot determine a category.
*
* If we are able to determine a type category, also notice whether any of
* the candidates takes a preferred datatype within the category.
*
* Having completed this examination, remove candidates that accept the
* wrong category at any unknown position. Also, if at least one
* candidate accepted a preferred type at a position, remove candidates
* that accept non-preferred types.
*
* If we are down to one candidate at the end, we win.
*/
resolved_unknowns = false;
for (i = 0; i < nargs; i++)
{
bool have_conflict;
if (input_base_typeids[i] != UNKNOWNOID)
continue;
resolved_unknowns = true; /* assume we can do it */
slot_category[i] = INVALID_TYPE;
slot_has_preferred_type[i] = false;
have_conflict = false;
for (current_candidate = candidates;
current_candidate != NULL;
current_candidate = current_candidate->next)
{
current_typeids = current_candidate->args;
current_type = current_typeids[i];
current_category = TypeCategory(current_type);
if (slot_category[i] == INVALID_TYPE)
{
/* first candidate */
slot_category[i] = current_category;
slot_has_preferred_type[i] =
IsPreferredType(current_category, current_type);
}
else if (current_category == slot_category[i])
{
/* more candidates in same category */
slot_has_preferred_type[i] |=
IsPreferredType(current_category, current_type);
}
else
{
/* category conflict! */
if (current_category == STRING_TYPE)
{
/* STRING always wins if available */
slot_category[i] = current_category;
slot_has_preferred_type[i] =
IsPreferredType(current_category, current_type);
}
else
{
/*
* Remember conflict, but keep going (might find STRING)
*/
have_conflict = true;
}
}
}
if (have_conflict && slot_category[i] != STRING_TYPE)
{
/* Failed to resolve category conflict at this position */
resolved_unknowns = false;
break;
}
}
if (resolved_unknowns)
{
/* Strip non-matching candidates */
ncandidates = 0;
last_candidate = NULL;
for (current_candidate = candidates;
current_candidate != NULL;
current_candidate = current_candidate->next)
{
bool keepit = true;
current_typeids = current_candidate->args;
for (i = 0; i < nargs; i++)
{
if (input_base_typeids[i] != UNKNOWNOID)
continue;
current_type = current_typeids[i];
current_category = TypeCategory(current_type);
if (current_category != slot_category[i])
{
keepit = false;
break;
}
if (slot_has_preferred_type[i] &&
!IsPreferredType(current_category, current_type))
{
keepit = false;
break;
}
}
if (keepit)
{
/* keep this candidate */
last_candidate = current_candidate;
ncandidates++;
}
else
{
/* forget this candidate */
if (last_candidate)
last_candidate->next = current_candidate->next;
else
candidates = current_candidate->next;
}
}
if (last_candidate) /* terminate rebuilt list */
last_candidate->next = NULL;
}
if (ncandidates == 1)
return candidates;
return NULL; /* failed to select a best candidate */
} /* func_select_candidate() */
/* func_get_detail()
*
* Find the named function in the system catalogs.
*
* Attempt to find the named function in the system catalogs with
* arguments exactly as specified, so that the normal case
* (exact match) is as quick as possible.
*
* If an exact match isn't found:
* 1) check for possible interpretation as a trivial type coercion
* 2) get a vector of all possible input arg type arrays constructed
* from the superclasses of the original input arg types
* 3) get a list of all possible argument type arrays to the function
* with given name and number of arguments
* 4) for each input arg type array from vector #1:
* a) find how many of the function arg type arrays from list #2
* it can be coerced to
* b) if the answer is one, we have our function
* c) if the answer is more than one, attempt to resolve the conflict
* d) if the answer is zero, try the next array from vector #1
*
* Note: we rely primarily on nargs/argtypes as the argument description.
* The actual expression node list is passed in fargs so that we can check
* for type coercion of a constant. Some callers pass fargs == NIL
* indicating they don't want that check made.
*/
FuncDetailCode
func_get_detail(List *funcname,
List *fargs,
int nargs,
Oid *argtypes,
Oid *funcid, /* return value */
Oid *rettype, /* return value */
bool *retset, /* return value */
bool *retstrict, /* return value */
bool *retordered, /* return value */
Oid **true_typeids) /* return value */
{
FuncCandidateList raw_candidates;
FuncCandidateList best_candidate;
/* Get list of possible candidates from namespace search */
raw_candidates = FuncnameGetCandidates(funcname, nargs);
/*
* Quickly check if there is an exact match to the input datatypes (there
* can be only one)
*/
for (best_candidate = raw_candidates;
best_candidate != NULL;
best_candidate = best_candidate->next)
{
if (memcmp(argtypes, best_candidate->args, nargs * sizeof(Oid)) == 0)
break;
}
if (best_candidate == NULL)
{
/*
* If we didn't find an exact match, next consider the possibility
* that this is really a type-coercion request: a single-argument
* function call where the function name is a type name. If so, and
* if we can do the coercion trivially (no run-time function call
* needed), then go ahead and treat the "function call" as a coercion.
* This interpretation needs to be given higher priority than
* interpretations involving a type coercion followed by a function
* call, otherwise we can produce surprising results. For example, we
* want "text(varchar)" to be interpreted as a trivial coercion, not
* as "text(name(varchar))" which the code below this point is
* entirely capable of selecting.
*
* "Trivial" coercions are ones that involve binary-compatible types
* and ones that are coercing a previously-unknown-type literal
* constant to a specific type.
*
* The reason we can restrict our check to binary-compatible coercions
* here is that we expect non-binary-compatible coercions to have an
* implementation function named after the target type. That function
* will be found by normal lookup if appropriate.
*
* NB: it's important that this code stays in sync with what
* coerce_type can do, because the caller will try to apply
* coerce_type if we return FUNCDETAIL_COERCION. If we return that
* result for something coerce_type can't handle, we'll cause infinite
* recursion between this module and coerce_type!
*/
if (nargs == 1 && fargs != NIL)
{
Oid targetType;
targetType = LookupTypeName(NULL,
makeTypeNameFromNameList(funcname));
if (OidIsValid(targetType) &&
!ISCOMPLEX(targetType))
{
Oid sourceType = argtypes[0];
Node *arg1 = linitial(fargs);
Oid cfuncid;
if ((sourceType == UNKNOWNOID && IsA(arg1, Const)) ||
(find_coercion_pathway(targetType, sourceType,
COERCION_EXPLICIT, &cfuncid) &&
cfuncid == InvalidOid))
{
/* Yup, it's a type coercion */
*funcid = InvalidOid;
*rettype = targetType;
*retset = false;
*retstrict = false;
*retordered = false;
*true_typeids = argtypes;
return FUNCDETAIL_COERCION;
}
}
}
/*
* didn't find an exact match, so now try to match up candidates...
*/
if (raw_candidates != NULL)
{
FuncCandidateList current_candidates;
int ncandidates;
ncandidates = func_match_argtypes(nargs,
argtypes,
raw_candidates,
&current_candidates);
/* one match only? then run with it... */
if (ncandidates == 1)
best_candidate = current_candidates;
/*
* multiple candidates? then better decide or throw an error...
*/
else if (ncandidates > 1)
{
best_candidate = func_select_candidate(nargs,
argtypes,
current_candidates);
/*
* If we were able to choose a best candidate, we're done.
* Otherwise, ambiguous function call.
*/
if (!best_candidate)
return FUNCDETAIL_MULTIPLE;
}
}
}
if (best_candidate)
{
HeapTuple ftup;
Form_pg_proc pform;
bool isagg = false;
cqContext *procqCtx;
*funcid = best_candidate->oid;
*true_typeids = best_candidate->args;
procqCtx = caql_beginscan(
NULL,
cql("SELECT * FROM pg_proc "
" WHERE oid = :1 ",
ObjectIdGetDatum(best_candidate->oid)));
ftup = caql_getnext(procqCtx);
if (!HeapTupleIsValid(ftup)) /* should not happen */
elog(ERROR, "cache lookup failed for function %u",
best_candidate->oid);
pform = (Form_pg_proc) GETSTRUCT(ftup);
*rettype = pform->prorettype;
*retset = pform->proretset;
*retstrict = pform->proisstrict;
*retordered = false;
isagg = pform->proisagg;
caql_endscan(procqCtx);
/*
* For aggregate functions STRICTness is defined by the
* transition function
*/
if (isagg)
{
Form_pg_aggregate aggform;
FmgrInfo transfn;
Datum value;
bool isnull;
cqContext *aggcqCtx;
aggcqCtx = caql_beginscan(
NULL,
cql("SELECT * FROM pg_aggregate "
" WHERE aggfnoid = :1 ",
ObjectIdGetDatum(best_candidate->oid)));
ftup = caql_getnext(aggcqCtx);
if (!HeapTupleIsValid(ftup)) /* should not happen */
elog(ERROR, "cache lookup failed for aggregate %u",
best_candidate->oid);
aggform = (Form_pg_aggregate) GETSTRUCT(ftup);
fmgr_info(aggform->aggtransfn, &transfn);
*retstrict = transfn.fn_strict;
/*
* Check if this is an ordered aggregate - while aggordered
* should never be null it comes after a variable length field
* so we must access it via caql_getattr.
*/
value = caql_getattr(aggcqCtx,
Anum_pg_aggregate_aggordered,
&isnull);
*retordered = (!isnull) && DatumGetBool(value);
caql_endscan(aggcqCtx);
return FUNCDETAIL_AGGREGATE;
}
return FUNCDETAIL_NORMAL;
}
return FUNCDETAIL_NOTFOUND;
}
/*
* Given two type OIDs, determine whether the first is a complex type
* (class type) that inherits from the second.
*/
bool
typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
{
bool result = false;
Oid relid;
Relation inhrel;
List *visited,
*queue;
ListCell *queue_item;
if (!ISCOMPLEX(subclassTypeId) || !ISCOMPLEX(superclassTypeId))
return false;
relid = typeidTypeRelid(subclassTypeId);
if (relid == InvalidOid)
return false;
/*
* Begin the search at the relation itself, so add relid to the queue.
*/
queue = list_make1_oid(relid);
visited = NIL;
inhrel = heap_open(InheritsRelationId, AccessShareLock);
/*
* Use queue to do a breadth-first traversal of the inheritance graph from
* the relid supplied up to the root. Notice that we append to the queue
* inside the loop --- this is okay because the foreach() macro doesn't
* advance queue_item until the next loop iteration begins.
*/
foreach(queue_item, queue)
{
Oid this_relid = lfirst_oid(queue_item);
cqContext *pcqCtx;
cqContext cqc;
HeapTuple inhtup;
/* If we've seen this relid already, skip it */
if (list_member_oid(visited, this_relid))
continue;
/*
* Okay, this is a not-yet-seen relid. Add it to the list of
* already-visited OIDs, then find all the types this relid inherits
* from and add them to the queue. The one exception is we don't add
* the original relation to 'visited'.
*/
if (queue_item != list_head(queue))
visited = lappend_oid(visited, this_relid);
pcqCtx = caql_beginscan(
caql_addrel(cqclr(&cqc), inhrel),
cql("SELECT * FROM pg_inherits "
" WHERE inhrelid = :1 ",
ObjectIdGetDatum(this_relid)));
while (HeapTupleIsValid(inhtup = caql_getnext(pcqCtx)))
{
Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inhtup);
Oid inhparent = inh->inhparent;
/* If this is the target superclass, we're done */
if (get_rel_type_id(inhparent) == superclassTypeId)
{
result = true;
break;
}
/* Else add to queue */
queue = lappend_oid(queue, inhparent);
}
caql_endscan(pcqCtx);
if (result)
break;
}
heap_close(inhrel, AccessShareLock);
list_free(visited);
list_free(queue);
return result;
}
/*
* make_fn_arguments()
*
* Given the actual argument expressions for a function, and the desired
* input types for the function, add any necessary typecasting to the
* expression tree. Caller should already have verified that casting is
* allowed.
*
* Caution: given argument list is modified in-place.
*
* As with coerce_type, pstate may be NULL if no special unknown-Param
* processing is wanted.
*/
void
make_fn_arguments(ParseState *pstate,
List *fargs,
Oid *actual_arg_types,
Oid *declared_arg_types)
{
ListCell *current_fargs;
int i = 0;
foreach(current_fargs, fargs)
{
/* types don't match? then force coercion using a function call... */
if (actual_arg_types[i] != declared_arg_types[i])
{
lfirst(current_fargs) = coerce_type(pstate,
lfirst(current_fargs),
actual_arg_types[i],
declared_arg_types[i], -1,
COERCION_IMPLICIT,
COERCE_IMPLICIT_CAST,
-1);
}
i++;
}
}
/*
* ParseComplexProjection -
* handles function calls with a single argument that is of complex type.
* If the function call is actually a column projection, return a suitably
* transformed expression tree. If not, return NULL.
*/
static Node *
ParseComplexProjection(ParseState *pstate, char *funcname, Node *first_arg,
int location)
{
TupleDesc tupdesc;
int i;
/*
* Special case for whole-row Vars so that we can resolve (foo.*).bar even
* when foo is a reference to a subselect, join, or RECORD function. A
* bonus is that we avoid generating an unnecessary FieldSelect; our
* result can omit the whole-row Var and just be a Var for the selected
* field.
*
* This case could be handled by expandRecordVariable, but it's more
* efficient to do it this way when possible.
*/
if (IsA(first_arg, Var) &&
((Var *) first_arg)->varattno == InvalidAttrNumber)
{
RangeTblEntry *rte;
rte = GetRTEByRangeTablePosn(pstate,
((Var *) first_arg)->varno,
((Var *) first_arg)->varlevelsup);
/* Return a Var if funcname matches a column, else NULL */
return scanRTEForColumn(pstate, rte, funcname, location);
}
/*
* Else do it the hard way with get_expr_result_type().
*
* If it's a Var of type RECORD, we have to work even harder: we have to
* find what the Var refers to, and pass that to get_expr_result_type.
* That task is handled by expandRecordVariable().
*/
if (IsA(first_arg, Var) &&
((Var *) first_arg)->vartype == RECORDOID)
tupdesc = expandRecordVariable(pstate, (Var *) first_arg, 0);
else if (get_expr_result_type(first_arg, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
return NULL; /* unresolvable RECORD type */
Assert(tupdesc);
for (i = 0; i < tupdesc->natts; i++)
{
Form_pg_attribute att = tupdesc->attrs[i];
if (strcmp(funcname, NameStr(att->attname)) == 0 &&
!att->attisdropped)
{
/* Success, so generate a FieldSelect expression */
FieldSelect *fselect = makeNode(FieldSelect);
fselect->arg = (Expr *) first_arg;
fselect->fieldnum = i + 1;
fselect->resulttype = att->atttypid;
fselect->resulttypmod = att->atttypmod;
return (Node *) fselect;
}
}
return NULL; /* funcname does not match any column */
}
/*
* helper routine for delivering "column does not exist" error message
*/
static void
unknown_attribute(ParseState *pstate, Node *relref, char *attname,
int location)
{
RangeTblEntry *rte;
if (IsA(relref, Var) &&
((Var *) relref)->varattno == InvalidAttrNumber)
{
/* Reference the RTE by alias not by actual table name */
rte = GetRTEByRangeTablePosn(pstate,
((Var *) relref)->varno,
((Var *) relref)->varlevelsup);
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column %s.%s does not exist",
rte->eref->aliasname, attname),
errOmitLocation(true),
parser_errposition(pstate, location)));
}
else
{
/* Have to do it by reference to the type of the expression */
Oid relTypeId = exprType(relref);
if (ISCOMPLEX(relTypeId))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" not found in data type %s",
attname, format_type_be(relTypeId)),
errOmitLocation(true),
parser_errposition(pstate, location)));
else if (relTypeId == RECORDOID)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("could not identify column \"%s\" in record data type",
attname),
errOmitLocation(true),
parser_errposition(pstate, location)));
else
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("column notation .%s applied to type %s, "
"which is not a composite type",
attname, format_type_be(relTypeId)),
errOmitLocation(true),
parser_errposition(pstate, location)));
}
}
/*
* funcname_signature_string
* Build a string representing a function name, including arg types.
* The result is something like "foo(integer)".
*
* This is typically used in the construction of function-not-found error
* messages.
*/
const char *
funcname_signature_string(const char *funcname,
int nargs, const Oid *argtypes)
{
StringInfoData argbuf;
int i;
initStringInfo(&argbuf);
appendStringInfo(&argbuf, "%s(", funcname);
for (i = 0; i < nargs; i++)
{
if (i)
appendStringInfoString(&argbuf, ", ");
appendStringInfoString(&argbuf, format_type_be(argtypes[i]));
}
appendStringInfoChar(&argbuf, ')');
return argbuf.data; /* return palloc'd string buffer */
}
/*
* func_signature_string
* As above, but function name is passed as a qualified name list.
*/
const char *
func_signature_string(List *funcname, int nargs, const Oid *argtypes)
{
return funcname_signature_string(NameListToString(funcname),
nargs, argtypes);
}
/*
* LookupFuncName
* Given a possibly-qualified function name and a set of argument types,
* look up the function.
*
* If the function name is not schema-qualified, it is sought in the current
* namespace search path.
*
* If the function is not found, we return InvalidOid if noError is true,
* else raise an error.
*/
Oid
LookupFuncName(List *funcname, int nargs, const Oid *argtypes, bool noError)
{
FuncCandidateList clist;
clist = FuncnameGetCandidates(funcname, nargs);
while (clist)
{
if (memcmp(argtypes, clist->args, nargs * sizeof(Oid)) == 0)
return clist->oid;
clist = clist->next;
}
if (!noError)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("function %s does not exist",
func_signature_string(funcname, nargs, argtypes)),
errOmitLocation(true)));
return InvalidOid;
}
/*
* LookupFuncNameTypeNames
* Like LookupFuncName, but the argument types are specified by a
* list of TypeName nodes.
*/
Oid
LookupFuncNameTypeNames(List *funcname, List *argtypes, bool noError)
{
Oid argoids[FUNC_MAX_ARGS];
int argcount;
int i;
ListCell *args_item;
argcount = list_length(argtypes);
if (argcount > FUNC_MAX_ARGS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
errmsg("functions cannot have more than %d arguments",
FUNC_MAX_ARGS)));
args_item = list_head(argtypes);
for (i = 0; i < argcount; i++)
{
TypeName *t = (TypeName *) lfirst(args_item);
argoids[i] = LookupTypeName(NULL, t);
if (!OidIsValid(argoids[i]))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("type \"%s\" does not exist",
TypeNameToString(t)),
errOmitLocation(true)));
args_item = lnext(args_item);
}
return LookupFuncName(funcname, argcount, argoids, noError);
}
/*
* LookupAggNameTypeNames
* Find an aggregate function given a name and list of TypeName nodes.
*
* This is almost like LookupFuncNameTypeNames, but the error messages refer
* to aggregates rather than plain functions, and we verify that the found
* function really is an aggregate.
*/
Oid
LookupAggNameTypeNames(List *aggname, List *argtypes, bool noError)
{
Oid argoids[FUNC_MAX_ARGS];
int argcount;
int i;
ListCell *lc;
Oid oid;
HeapTuple ftup;
Form_pg_proc pform;
cqContext *pcqCtx;
bool proisagg;
argcount = list_length(argtypes);
if (argcount > FUNC_MAX_ARGS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
errmsg("functions cannot have more than %d arguments",
FUNC_MAX_ARGS)));
i = 0;
foreach(lc, argtypes)
{
TypeName *t = (TypeName *) lfirst(lc);
argoids[i] = LookupTypeName(NULL, t);
if (!OidIsValid(argoids[i]))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("type \"%s\" does not exist",
TypeNameToString(t)),
errOmitLocation(true)));
i++;
}
oid = LookupFuncName(aggname, argcount, argoids, true);
if (!OidIsValid(oid))
{
if (noError)
return InvalidOid;
if (argcount == 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("aggregate %s(*) does not exist",
NameListToString(aggname)),
errOmitLocation(true)));
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("aggregate %s does not exist",
func_signature_string(aggname,
argcount, argoids)),
errOmitLocation(true)));
}
/* Make sure it's an aggregate */
/* SELECT proisagg FROM pg_proc */
pcqCtx = caql_beginscan(
NULL,
cql("SELECT * FROM pg_proc "
" WHERE oid = :1 ",
ObjectIdGetDatum(oid)));
ftup = caql_getnext(pcqCtx);
if (!HeapTupleIsValid(ftup)) /* should not happen */
elog(ERROR, "cache lookup failed for function %u", oid);
pform = (Form_pg_proc) GETSTRUCT(ftup);
proisagg = pform->proisagg;
caql_endscan(pcqCtx);
if (!proisagg)
{
if (noError)
return InvalidOid;
/* we do not use the (*) notation for functions... */
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("function %s is not an aggregate",
func_signature_string(aggname,
argcount, argoids))));
}
return oid;
}
/*
* parseCheckTableFunctions
*
* Check for TableValueExpr where they shouldn't be. Currently the only
* valid location for a TableValueExpr is within a call to a table function.
* In the full SQL Standard they can exist anywhere a multiset is supported.
*/
void
parseCheckTableFunctions(ParseState *pstate, Query *qry)
{
check_table_func_context context;
context.parent = NULL;
query_tree_walker(qry,
checkTableFunctions_walker,
(void *) &context, 0);
}
static bool
checkTableFunctions_walker(Node *node, check_table_func_context *context)
{
if (node == NULL)
return false;
/*
* TABLE() value expressions are currently only permited as parameters
* to table functions called in the FROM clause.
*/
if (IsA(node, TableValueExpr))
{
if (context->parent && IsA(context->parent, FuncExpr))
{
FuncExpr *parent = (FuncExpr *) context->parent;
/*
* This flag is set in addRangeTableEntryForFunction for functions
* called as range table entries having TABLE value expressions
* as arguments.
*/
if (parent->is_tablefunc)
return false;
/* Error message could be improved */
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("table functions must be invoked in FROM clause")));
}
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("invalid use of TABLE value expression")));
return true; /* not possible, but keeps compiler happy */
}
context->parent = node;
if (IsA(node, Query))
{
return query_tree_walker((Query *) node,
checkTableFunctions_walker,
(void *) context, 0);
}
else
{
return expression_tree_walker(node,
checkTableFunctions_walker,
(void *) context);
}
}